/usr/share/vim/vim74/syntax/phtml.vim is in vim-runtime 2:7.4.052-1ubuntu3.
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 | " Vim syntax file
" PHTML used to be the filetype for PHP 2.0. Now everything is PHP.
if !exists("b:current_syntax")
runtime! syntax/php.vim
endif
|