/usr/share/vim/vim80/ftplugin/diff.vim is in vim-runtime 2:8.0.1453-1ubuntu1.
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 | " Vim filetype plugin file
" Language: Diff
" Maintainer: Bram Moolenaar <Bram@vim.org>
" Last Change: 2005 Jul 27
" Only do this when not done yet for this buffer
if exists("b:did_ftplugin")
finish
endif
let b:did_ftplugin = 1
let b:undo_ftplugin = "setl modeline<"
" Don't use modelines in a diff, they apply to the diffed file
setlocal nomodeline
|