/usr/share/nano/groff.nanorc is in nano 2.5.3-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | ## Here is an example for groff.
syntax "groff" "\.m[ems]$" "\.rof" "\.tmac$" "^tmac."
# The argument of .ds or .nr
color cyan "^\.(ds|nr) [^[:space:]]*"
# Single-character escapes
color brightmagenta "\\."
# The argument of \f or \s in the same color
color brightmagenta "\\f." "\\f\(.." "\\s(\+|\-)?[0-9]"
# Newlines
color cyan "(\\|\\\\)n(.|\(..)"
color cyan start="(\\|\\\\)n\[" end="]"
# Requests
color brightgreen "^\.[[:space:]]*[^[:space:]]*"
# Comments
color yellow "^\.\\".*$"
# Strings
color green "(\\|\\\\)\*(.|\(..)"
color green start="(\\|\\\\)\*\[" end="]"
# Characters
color brightred "\\\(.."
color brightred start="\\\[" end="]"
# Macro arguments
color brightcyan "\\\\\$[1-9]"
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