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groff_man

Section: Environments, Tables, and Troff Macros (7)
Updated: 202-0-28
Index Return to Main Contents

Name

groff_man - compose manual pages with GNU roff
.nr d-fallback 1
.nr d-fallback 1

Synopsis

[option~...] [file~...] [option~...] [file~...]

Description

The GNU implementation of the man macro package is part of the groff document formatting system. It is used to compose manual pages ([lq]man~pages[rq]) like the one you are reading. This document presents the macros thematically; for those needing only a quick reference, the following table lists them alphabetically, with references to appropriate subsections below. Readers who are not already experienced groff users should consult an expanded version of this document, for additional explanations and advice. It covers only those concepts required for man page document maintenance, and not the full breadth of the groff typesetting system.

" begin shameless cheat for slim terminals

Macro	Meaning	Subsection

.B	Bold	Font style macros
.BI	Bold, italic alternating	Font style macros
.BR	Bold, roman alternating	Font style macros
.EE	Example end	Document structure macros
.EX	Example begin	Document structure macros
.HP	Begin hanging paragraph	Paragraphing macros
.I	Italic	Font style macros
.IB	Italic, bold alternating	Font style macros
.IP	Indented paragraph	Paragraphing macros
.IR	Italic, roman alternating	Font style macros
.LP	Begin paragraph	Paragraphing macros
.ME	Mai-to end	Hyperlink macros
.MR	Man page cross reference	Hyperlink macros
.MT	Mai-to start	Hyperlink macros
.P	Begin paragraph	Paragraphing macros
.PP	Begin paragraph	Paragraphing macros
.RB	Roman, bold alternating	Font style macros
.RE	Relative inset end	Document structure macros
.RI	Roman, italic alternating	Font style macros
.RS	Relative inset start	Document structure macros
.SH	Section heading	Document structure macros
.SM	Small	Font style macros
.SS	Subsection heading	Document structure macros
.SY	Synopsis start	Synopsis macros
.TH	Title heading	Document structure macros
.TP	Tagged paragraph	Paragraphing macros
.TQ	Supplemental paragraph tag	Paragraphing macros
.UE	URI end	Hyperlink macros
.UR	URI start	Hyperlink macros
.YS	Synopsis end	Synopsis macros

We discuss other macros (AT, DT, OP, PD, SB, and UC) in subsection [lq]Deprecated features[rq] below. Throughout Unix documentation, a manual entry is referred to simply as a [lq]man page[rq], regardless of its length, without gendered implication, and irrespective of the macro package selected for its composition.

Macro reference preliminaries

A tagged paragraph describes each macro. We present coupled pairs together, as with EX and EE. If you require an empty macro argument, specify it as a pair of neutral double quotes ([dq][dq]). Most macro arguments are formatted as text in the output; exceptions are noted.

Document structure macros

Document structure macros organize a man page's content. All of them break the output line. TH (title heading) identifies the document as a man page and configures the page headers and footers. Section headings (SH), one of which is mandatory and many of which are conventionally expected, facilitate location of material by the reader and aid the man page writer to discuss all essential aspects of the topics presented. Subsection headings (SS) are optional and permit sections that grow long to develop in a controlled way. Many technical discussions benefit from examples; lengthy ones, especially those reflecting multiple lines of input to or output from the system, are usefully bracketed by EX and EE. When none of the foregoing meets a structural demand, use RS/RE to inset a region within a (sub)section.

.TH identifier section~

[foote-middle~[foote-inside~[heade-middle]]] Break the page, reset the page number to~1 (unless the -rC1 option is given), and use the arguments to populate the page header and footer. Together, identifier and the section of the manual to which it belongs can uniquely identify a man document on the system. See or for the manual sectioning applicable to your system. identifier and section are positioned at the left and right in the header; the latter is set after the former, in parentheses and without space. foote-middle is centered in the footer. By default, foote-inside is positioned at the bottom left. Use of the doubl-sided layout option -rD1 places foote-inside at the bottom left on recto (od-numbered) pages, and the bottom right on verso (eve-numbered) pages. By default, the outside footer is the page number. Use of the continuou-rendering option -rcR=1 replaces it with identifier and section, as in the header. heade-middle is centered in the header. If section is an integer between 1 and~9 (inclusive), there is no need to specify heade-middle; an.tmac supplies text for it. If identifier or foote-inside would overrun the space available in the header and/or footer, this package may abbreviate them with ellipses. groff man suppresses headers and footers in HTML output.

A valid man document calls TH only once, early in the file, prior to any other macro calls.

.SH [

headin-text] Set headin-text as a section heading. Given no argument, SH plants a on-line input trap; text on the next line becomes headin-text. The heading text is set in bold (or the font specified by the string HF), and, on typesetters, slightly larger than the base type size. If the heading font [rs]*[HF] is bold, use of an italic style in headin-text is mapped to the bol-italic style if available in the font family. The inset level is reset to 1; see subsection [lq]Horizontal and vertical spacing[rq] below. Text lines after the call are set as an ordinary paragraph (P).

The content of headin-text and ordering of sections follows a set of common practices, as does much of the layout of material within sections. For example, a section called [lq]Name[rq] or [lq]NAME[rq] must exist, must be the first section after the TH call, and must contain only text of the form

" Invisibly move left margin to current IP indentation.

: " Now indent further, visibly. topic[, anothe-topic]... - summar-description

for tools like or to index them.

.SS [

subheadin-text] Set subheadin-text as a subsection heading indented between a section heading and an ordinary paragraph (P). Given no argument, SS plants a on-line input trap; text on the next line becomes subheadin-text. The subheading text is set in bold (or the font specified by the string HF). If the heading font [rs]*[HF] is bold, use of an italic style in subheadin-text is mapped to the bol-italic style if available in the font family. The inset level is reset to 1; see subsection [lq]Horizontal and vertical spacing[rq] below. Text lines after the call are set as an ordinary paragraph (P).

.EX

.EE Begin and end example. After EX, filling is disabled (and, on typesetters, a monospaced font family is selected). Calling EE enables filling (and restores the previous family).

Ninth Edition Unix introduced the EX and EE extensions. Documenter's Workbench (DWB), Heirloom Doctools, and Plan~9 troffs, and mandoc (since 1.12.2) support them. Solaris troff does not.

.RS [

inse-amount] Start new relative inset. man saves any current inset amount and moves right by: inse-amount, if specified; the indentation amount of the preceding IP, TP, or HP macro call if no (su-)sectioning or ordinary paragraphing macro has intervened; or the amount of the IN register. RS calls can nest; each increments by~1 the level used by RE. The level prior to any RS call is~1.

.RE [

inse-level] End a relative inset, reducing it to that of inse-level (or by~1 if not specified) and restoring the corresponding inset amount.

Paragraphing macros

These macros break the output line. An ordinary paragraph (P) indents all output lines by the same amount. A hanging paragraph (HP) is a cosmetic variant of P with a hanging indent. Definition lists frequently occur in man pages; these can be set as tagged paragraphs, which have one (TP) or more (TQ) leading tags followed by a paragraph that has an additional indentation. The indented paragraph (IP) macro can continue the indented content of a narrative started with TP, or present an itemized or ordered list. If a paragraphing macro has been called since SH or SS, all except TQ follow the break with vertical space (in an amount configured by the deprecated PD macro); see subsection [lq]Horizontal and vertical spacing[rq] below. Except for TQ, these macros reset the type size, hyphenation, and adjustment to (configured) defaults, and the font style to roman.

.P: .LP .PP Begin a new paragraph; these macros are synonymous. Any indentation from use of IP, TP, or HP is cleared. The inset amount, as affected by RS and RE, is not.
.HP [: indentation] Set a paragraph with a hanging indentation. Text on output lines after the first is indented by indentation, if specified, and by the amount of the IN register otherwise.
: Caution: A hanging indentation cannot be expressed naturally in (pure) HTML, a hanging paragraph is not distinguishable from an ordinary one if it formats on only one output line, and no-roff-based man page interpreters may treat HP as an ordinary paragraph anyway. Thus, information or distinctions you mean to express with indentation may be lost.
.TP [: indentation] Set an indented paragraph with a leading unindented tag. The macro plants a on-line input trap that honors the [rs]c escape sequence; text on the next line becomes the tag, set without indentation. Text on subsequent lines is indented by indentation, if specified, and by the amount of the IN register otherwise. If the tag, plus the [lq]tag spacing[rq] stored in the TS register (see section [lq]Options[rq] below) is wider than the indentation, the package breaks the line after the tag.
.TQ: Set an additional tag for a paragraph tagged with TP, planting a on-line input trap as with TP.
: TQ is a GNU extension supported by Heirloom Doctools troff (since Git snapshot 151218) and mandoc (since 1.14.5) but not by DWB, Plan~9, or Solaris troffs.
.IP~[: mark~[indentation]] Set an indented paragraph with an optional mark. Arguments, if present, are handled as with TP, except that the mark argument to IP cannot include a macro call, and the tag separation amount stored in the TS register is not enforced.

Synopsis macros

Use SY and YS to summarize syntax using familiar Unix conventions. Heirloom Doctools troff (since Git snapshot 151218) and mandoc (since 1.14.5) support these GNU extensions; DWB, Plan~9, and Solaris troffs do not.

.SY~keyword~: [suffix] Begin synopsis. Adjustment and automatic hyphenation are disabled. If SY has already been called without a corresponding YS, a break is performed. keyword and any suffix are set in bold. When suffix is present, the package sets the next word after it without intervening space. If a break is required in subsequent text (up to a paragraphing, sectioning, or YS macro call), lines after the first are indented. Unless the previous synopsis's indentation is reused (see YS below), output lines after the first indent by the width of the pending output line up to the end of keyword plus a space, if keyword is the only argument, and up to the end of suffix otherwise.
.YS~[: reus-indentation] End synopsis, breaking the line and restoring indentation, adjustment, and hyphenation to their previous states. If an argument is given, the indentation corresponding to the previous SY call is reused by the next SY call instead of being computed.

Hyperlink macros

Man page cross references are best presented with MR. Mark email addresses with MT/ME and other sorts of URI with UR/UE. To hyperlink text, terminals and pager programs must support ECM-48 OSC~8 escape sequences (see When device support is unavailable or disabled with the U register (see section [lq]Options[rq] below), groff man renders these URIs between angle brackets ([la]~[ra]) after the linked text. MT, ME, UR, and UE are GNU extensions supported by Heirloom Doctools troff (since Git snapshot 151218) and mandoc (UR/UE since 1.12.3; MT/ME since 1.14.2) but not by DWB, Plan~9 (original), or Solaris troffs. Plan~9 from User Space's troff implements MR.
Prepare arguments to MR, MT, and UR for typesetting; they can appear in the output. Use special character escape sequences to encode Unicode basic Latin characters where necessary, particularly the hyphe-minus.

.MR~topic: ~[manua-section~[trailin-text]] (since~groff~1.23) Set a man page cross reference as [lq]topic(manua-section)[rq]. If manua-section is absent, the package omits the surrounding parentheses. If trailin-text (typically punctuation) is specified, it follows the closing parenthesis without intervening space. Hyphenation is disabled while the cross reference is set. topic is set in the font specified by the MF string. If manua-section is present, the cross reference hyperlinks to a URI of the form [lq]man:topic(manua-section)[rq].
.MT address: .ME [trailin-text] Identify address as an RFC 6068 add-spec for a [lq]mailto:[rq] URI with the text between the two macro calls as the link text. An argument to ME is placed after the link text without intervening space. address may not be visible in the rendered document if hyperlinks are enabled and supported by the output driver. If they are not, address is set in angle brackets after the link text and before trailin-text. If hyperlinking is enabled but there is no link text, address is formatted and hyperlinked without angle brackets, except when address appears as a TP paragraph tag.
.UR uri: .UE [trailin-text] Identify uri as an RFC 3986 URI hyperlink with the text between the two macro calls as the link text. An argument to UE is placed after the link text without intervening space. uri may not be visible in the rendered document if hyperlinks are enabled and supported by the output driver. If they are not, uri is set in angle brackets after the link text and before trailin-text. If hyperlinking is enabled but there is no link text, uri is formatted and hyperlinked without angle brackets, except when uri appears as a TP paragraph tag. If a UR/UE or MT/ME pair occurs in a TP tag and hyperlinking is unavailable, groff man sets the link target at the beginning of the indented paragraph, not as part of the tag, unless there is no link text.

Font style macros

The man macro package is limited in its font styling options, offering only bold~(B), italic~(I), and roman. Italic text may instead render underscored on terminals. SM sets text at a smaller type size, which differs visually from regula-sized text only on typesetters. The macros BI, BR, IB, IR, RB, and RI set their od- and eve-numbered arguments as text in the alternating styles their names indicate, with no space separating them. The default type size and family for typesetters is 1-point Times, except on the X75-12 and X100-12 devices where the type size is 12 points. The default style is roman.

.B~[: text] Set text in bold. Given no argument, B plants a on-line input trap; text on the next line, which can be further formatted with a macro, is set in bold.
.I~[: text] Set text in an italic or oblique face. Given no argument, I plants a on-line input trap; text on the next line, which can be further formatted with a macro, is set in an italic or oblique face.
.SM~[: text] Set text one point smaller than the default type size on typesetters. Given no argument, SM plants a on-line input trap; text on the next line, which can be further formatted with a macro, is set smaller.
Unlike the above font style macros, the font style alternation macros below set no input traps; they must be given arguments to have effect. They apply italic corrections as appropriate.
.BI bol-text itali-text: ... Set each argument in bold and italics, alternately.
.BR bol-text roma-text: ... Set each argument in bold and roman, alternately.
.IB itali-text bol-text: ... Set each argument in italics and bold, alternately.
.IR itali-text roma-text: ... Set each argument in italics and roman, alternately.
.RB roma-text bol-text: ... Set each argument in roman and bold, alternately.
.RI roma-text itali-text: ... Set each argument in roman and italics, alternately.

Horizontal and vertical spacing

The package sets all text inboard of the left edge of the output medium by the amount of the page offset; see register PO in section [lq]Options[rq] below. Headers, footers (both set with TH), and section headings (SH) lie at the page offset. groff man indents subsection headings (SS) by the amount in the SN register. Ordinary paragraphs not within an RS/RE inset region are inset by the amount stored in the BP register; see section [lq]Options[rq] below. The IN register configures the default indentation amount used by RS (as the inse-amount), IP, TP, and HP; an overriding argument is a number plus an optional scaling unit. If no scaling unit is given, the man package assumes [lq]n[rq]. An indentation specified in a call to IP, TP, or HP persists until (1) another of these macros is called with an indentation argument, or (2) SH, SS, or P or its synonyms is called; these clear the indentation entirely. Several macros insert vertical space: SH, SS, TP, P (and its synonyms), IP, and HP. They then enable n-space mode; see The default inte-section and inte-paragraph spacing is 1v for terminals and 0.4v for typesetters. (The deprecated macro PD can change this vertical spacing, but we discourage its use.) Between EX and EE calls, the inte-paragraph spacing is 1v regardless of output device.

Registers

Registers are described in section [lq]Options[rq] below. They can be set not only on the command line but in the site man.local file as well; see section [lq]Files[rq] below.

Strings

The following strings are defined for use in man pages. None of these is necessary in a contemporary man page; see groff man supports others for configuration of rendering parameters; see section [lq]Options[rq] below.

*R: interpolates a special character escape sequence for the [lq]registered sign[rq] glyph, (rg, if available, and [lq](Reg.)[rq] otherwise.
*S: interpolates an escape sequence setting the type size to the document default.
*(lq: *(rq interpolate special character escape sequences for left and right doubl-quotation marks, (lq and (rq, respectively.
*(Tm: interpolates a special character escape sequence for the [lq]trade mark sign[rq] glyph, (tm, if available, and [lq](TM)[rq] otherwise.

Hooks

Two macros, both GNU extensions,are called internally by the groff man package to format page headers and footers and can be redefined by the administrator in a site's man.local file (see section [lq]Files[rq] below). The presentation of TH above describes the default headers and footers. Because these macros are hooks for groff man internals, man pages have no reason to call them. Such hook definitions typically consist of [lq]sp[rq] and [lq]tl[rq] requests. PT furthermore has the responsibility of emitting a PDF bookmark after writing the first page header in a document. Consult the existing implementations in an.tmac when drafting replacements.

.BT: Set the page footer text ([lq]bottom trap[rq]).
.PT: Set the page header text ([lq]page trap[rq]). To remove a page header or footer entirely, define the appropriate macro as empty rather than deleting it.

Deprecated features

Use of the following in man pages for public distribution is discouraged.

.AT [

system [release]] Alter the footer for use with legacy AT&T man pages, overriding any definition of the foote-inside argument to TH. This macro exists only to render man pages from historical systems.

The inside footer is populated per the value of system.

" Invisibly move left margin to current IP indentation.

" Now indent further, visibly.

3: 7th edition (default)
4: System III
5: System V

The optional release argument specifies the release number, as in [lq]System~V Release~3[rq].

.DT

Reset tab stops to the default (every 0.5i).

Use of this presentatio-oriented macro is deprecated. It translates poorly to HTML, under which exact space control and tabulation are not readily available. Thus, information or distinctions that you use tab stops to express are likely to be lost. If you feel tempted to change the tab stops such that calling this macro later to restore them is desirable, consider composing a table using instead.

.OP optio-name/

[optio-argument] Indicate an optional command parameter called optio-name, which is set in bold. If the option takes an argument, specify optio-argument using a noun, abbreviation, or hyphenated noun phrase. If present, optio-argument is preceded by a space and set in italics. Square brackets in roman surround both arguments.

Use of this quas-semantic macro, an extension whose name originated in DWB troff, is deprecated; groff's interface differs. Neither can easily be used to annotate options that take optional arguments or options whose arguments have internal structure (such as a mixture of literal and variable components). One could work around these limitations with font selection escape sequences, but font style alternation macros are preferable; they are more flexible and perform italic corrections on typesetters.

.PD [

vertica-space] Configure the amount of vertical space between paragraphs or (sub)sections. The optional argument vertica-space specifies the amount; the default scaling unit is [lq]v[rq]. Without an argument, inte-paragraph spacing resets to its default value; see subsection [lq]Horizontal and vertical spacing[rq] above.

Use of this presentatio-oriented macro is deprecated. It translates poorly to HTML, under which exact control of inte-paragraph spacing is not readily available. Thus, information or distinctions that you use PD to express are likely to be lost.

.SB~[

text] Set text in bold and (on typesetters) one point smaller than the default type size. Given no argument, SB plants a on-line input trap; text on the next line, which can be further formatted with a macro, is set smaller and in bold. Use of this macro, an extension originating in SunOS~4.0 troff, is deprecated. SM without an argument, followed immediately by [lq]B text[rq], produces the same output more portably. The macros' order is interchangeable; put text with the latter.

.UC [

version] Alter the footer for use with legacy BSD man pages, overriding any definition of the foote-inside argument to TH. This macro exists only to render man pages from historical systems.

The inside footer is populated per the value of version.

" Invisibly move left margin to current IP indentation.

" Now indent further, visibly.

: 3 3rd Berkeley Distribution (default)
4: 4th Berkeley Distribution
5: 4.2 Berkeley Distribution
6: 4.3 Berkeley Distribution
7: 4.4 Berkeley Distribution

History

M. Douglas McIlroy designed, implemented, and documented the AT&T man macros for Unix Version~7 (1979) and employed them to edit Volume~1 of its Programmer's Manual, a compilation of all man pages supplied by the system. The package supported the macros listed in this page not described as extensions, except P and the deprecated AT and UC. It documented no registers and defined only R and S strings. UC appeared in 3BSD (1980). Unix System~III (1980) introduced P and exposed the registers IN and LL, which had been internal to Seventh Edition Unix man. PWB/Unix 2.0 (1980) added the Tm string. 4BSD (1980) added lq and rq strings. SunOS~2.0 (1985) recognized C, D, P, and X registers. 4.3BSD (1986) added AT and P. Ninth Edition Unix (1986) introduced EX and EE. SunOS~4.0 (1988) added SB. Unix System~V (1988) incorporated the lq and rq strings. Except for EX/EE, James Clark implemented the foregoing features in early versions of groff. Later, groff 1.20 (2009) resurrected EX/EE and originated SY/YS, TQ, MT/ME, and UR/UE. Plan~9 from User Space's troff introduced MR in 2020, and incorporated the lq and rq strings in 2025.

Options

The following groff options set registers (with -r) and strings (with -d) recognized and used by the man macro package. To ensure rendering consistent with output device capabilities and reader preferences, man pages should never manipulate them.

-dAD=adjustmen-mode: Set line adjustment to adjustmen-mode, which is typically [lq]b[rq] for adjustment to both margins (the default), or [lq]l[rq] for left alignment (ragged right margin). Any valid argument to groff's [lq]ad[rq] request may be used. See for les-common choices.
-rBP=bas-paragrap-inset: Set the inset amount for ordinary paragraphs not within an RS/RE inset. The default is~5n.
-rcR=1: Enable continuous rendering. Output is not paginated; instead, one (potentially very long) page is produced. This is the default for terminal and HTML devices. Use -rcR=0 to disable it on terminals; on HTML devices, it cannot be disabled.
-rC1: Number output pages consecutively, in strictly increasing sequence, rather than resetting the page number to~1 (or the value of register P) with each new man document.
-rCHECKSTYLE=n: Report problems with usage of this macro package exhibited by the input at verbosity level n, where n is an integer in the range 0[en]3, inclusive; 0 disables the messages and is the default. This feature is a development and debugging aid for man page maintainers; the problems diagnosed, and range and meanings of the supported levels, are subject to change.
-rCS=1: Set section headings (the argument(s) to SH) in full capitals. This transformation is off by default because it discards lettercase distinctions.
-rCT=1: Set the man page identifier (the first argument to TH) in full capitals in headers and footers. This transformation is off by default because it discards lettercase distinctions.
-rD1: Enable doubl-sided layout, formatting footers for even and odd pages differently; see the description of TH in subsection [lq]Document structure macros[rq] above.
-rFT=foote-distance: Set distance of the footer relative to the bottom of the page to foote-distance; this amount is always negative. At one hal-inch above this location, the page text is broken before writing the footer. Ignored if continuous rendering is enabled. The default is [lq]-0.5i~-~1v[rq].
-dHF=headin-font: Select the font used for section and subsection headings; the default is [lq]B[rq] (bold style of the default family). Any valid argument to groff's [lq]ft[rq] request may be used. See
-rHY=0: Disable automatic hyphenation. Normally, it is enabled~(1). The hyphenation mode is determined by the groff locale; see section [lq]Localization[lq] of
-rIN=standar-indentation: Set the default indentation amount used by IP, TP, and HP, and the inset amount used by RS. The default is 7n on terminals and 7.2n on typesetters. Use only integer multiples of unit [lq]n[rq] on terminals for consistent indentation.
-rLL=lin-length: Set line length; the default is 80n on terminals and 6.5i on typesetters.
-rLT=titl-length: Set the line length for titles. By default, it is set to the line length (see -rLL above).
-dMF=ma-pag-topi-font: Select the font used for man page identifiers in TH calls and topics named in MR calls; the default is [lq]I[rq] (italic style of the default family). Any valid argument to groff's [lq]ft[rq] request may be used. If the MF string ends in [lq]I[rq], the package assumes it to be an oblique typeface, and applies italic corrections before and after man page topics and identifiers.
-rPn: Start enumeration of pages at n. The default is~1.
-rPO=pag-offset: Set page offset; the default is 0 on terminals and 1i on typesetters.
-rStyp-size: Use typ-size for the document's body text; acceptable values are 10, 11, or 12 points. See subsection [lq]Font style macros[rq] above for the default.
-rSN=subsectio-indentation: Set indentation of subsection headings to subsectio-indentation. The default is~3n.
-rTS=separation: Require the given separation between a TP paragraph's tag and its body. The default is~2n.
-rU0: Disable generation of URI hyperlinks in output drivers capable of them, making the arguments to MT and UR calls visible as formatted text. and enable hyperlinks by default (the last only if not in its legacy output mode).
-rXp: Number successors of page~p as pa, pb, pc, and so forth. The register tracking the suffixed page letter uses format [lq]a[rq] (see the [lq]af[rq] request in

Files

/usr/:share/:groff/:1.24.2/:tmac/:an:.tmac: Most man macros are defined in this file. It also loads extensions from an-ext.tmac (see below).
/usr/:share/:groff/:1.24.2/:tmac/:andoc:.tmac: This brief groff program detects whether the man or mdoc macro package is used by a document and loads the correct macro definitions, taking advantage of the fact that pages using them must call TH or Dd, respectively, before any other macros. A man program or a user typing, for example, [lq]groff -mandoc page.1[rq], need not know which package the file page.1 uses. Multiple man pages, in either format, can be handled; andoc reloads each macro package as necessary. Pag-local redefinitions of names used by the man or mdoc packages prior to TH or Dd calls are [lq]clobbered[rq] by the reloading process. If you want to provide your own definition of an extension macro to ensure its availability, the an-ext:.tmac entry below offers advice.
/usr/:share/:groff/:1.24.2/:tmac/:an-ext:.tmac: Definitions of macros described above as extensions (and not deprecated) are contained in this file; in some cases, they are simpler versions of definitions appearing in an.tmac, and are ignored if the formatter is GNU troff. They are written to be compatible with AT&T troff and permissively licensed[em]not copylefted. To reduce the risk of name space collisions, string and register names begin only with [lq]m[rq]. We encourage man page authors who are concerned about portability to legacy Unix systems to copy these definitions into their pages, and maintainers of troff implementations or wor-alike systems that format man pages to r-use them. To ensure reliable rendering, define them after your page calls TH; see the discussion of andoc:.tmac above. Further, it is wise to define such pag-local macros (if at all) after the [lq]Name[rq] section to accommodate timid or implementations that easily give up scanning for indexing material.
/usr/:share/:groff/:1.24.2/:tmac/:man:.tmac: is a wrapper enabling the package to be loaded with the option [lq]-m man[rq].
/usr/:share/:groff/:1.24.2/:tmac/:mandoc:.tmac: is a wrapper enabling andoc.tmac to be loaded with the option [lq]-m mandoc[rq].
/usr/:share/:groff/:site-tmac/:man:.local: Put sit-local changes and customizations into this file.

Authors

James Clark wrote the initial GNU implementation of the man macro package. Later, Werner Lemberg supplied the S, LT, and cR registers, the last a 4.3BS-Reno mdoc(7) feature. Larry Kollar added the FT, HY, and SN registers; the HF string; and the PT and BT macros in groff 1.19 (2003). Lemberg and Eric S. Raymond contributed EX/EE, MT/ME, UR/UE, TQ, and an early version of the SY/YS macros to groff 1.20 (2009). G. Branden Robinson implemented the AD and MF strings; CS, CT, and U registers; and the MR macro for groff 1.23 (2023), and the BP, PO, and TS registers and a revised implementation of the SY/YS macros for groff 1.24 (2026). Susan G. Kleinmann wrote the initial version of this document for the Debian GNU/Linux system. Lemberg imported it to groff. He and Robinson revised and updated it. Raymond and Robinson documented the extension macros.