commit https://github.com/vim/vim/commit/2faa29f896252073b53f387406109e331fbbe5f8 Author: Bram Moolenaar <Bram@vim.org> Date: Sat Jan 23 23:02:34 2016 +0100 patch 7.4.1161 Problem: ":argadd" without argument is supposed to add the current buffer name to the arglist. Solution: Make it work as documented. (Coot, closes https://github.com/vim/vim/issues/577)

" 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