/usr/share/vim/vim74/syntax/config.vim is in vim-runtime 2:7.4.052-1ubuntu3.1.
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 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 | " Vim syntax file
" Language:		configure.in script: M4 with sh
" Maintainer:	Christian Hammesr <ch@lathspell.westend.com>
" Last Change:	2008 Sep 03
" Well, I actually even do not know much about m4. This explains why there
" is probably very much missing here, yet !
" But I missed a good hilighting when editing my GNU autoconf/automake
" script, so I wrote this quick and dirty patch.
" For version 5.x: Clear all syntax items
" For version 6.x: Quit when a syntax file was already loaded
if version < 600
  syntax clear
elseif exists("b:current_syntax")
  finish
endif
" define the config syntax
syn match   configdelimiter "[()\[\];,]"
syn match   configoperator  "[=|&\*\+\<\>]"
syn match   configcomment   "\(dnl.*\)\|\(#.*\)"
syn match   configfunction  "\<[A-Z_][A-Z0-9_]*\>"
syn match   confignumber    "[-+]\=\<\d\+\(\.\d*\)\=\>"
syn keyword configkeyword   if then else fi test for in do done
syn keyword configspecial   cat rm eval
syn region  configstring    start=+"+ skip=+\\"+ end=+"+
syn region  configstring    start=+'+ skip=+\\'+ end=+'+
syn region  configstring    start=+`+ skip=+\\'+ end=+`+
" Define the default highlighting.
" For version 5.7 and earlier: only when not done already
" For version 5.8 and later: only when an item doesn't have highlighting yet
if version >= 508 || !exists("did_config_syntax_inits")
  if version < 508
    let did_config_syntax_inits = 1
    command -nargs=+ HiLink hi link <args>
  else
    command -nargs=+ HiLink hi def link <args>
  endif
  HiLink configdelimiter Delimiter
  HiLink configoperator  Operator
  HiLink configcomment   Comment
  HiLink configfunction  Function
  HiLink confignumber    Number
  HiLink configkeyword   Keyword
  HiLink configspecial   Special
  HiLink configstring    String
  delcommand HiLink
endif
let b:current_syntax = "config"
" vim: ts=4
 |