The plugin directory is for standard Vim plugin scripts.

All files here ending in .vim will be sourced by Vim when it starts up.
Look in the file for hints on how it can be disabled without deleting it.

getscriptPlugin.vim  get latest version of Vim scripts
gzip.vim	     edit compressed files
logiPat.vim	     logical operators on patterns
manpager.vim	     using Vim as manpager
matchparen.vim	     highlight paren matching the one under the cursor
netrwPlugin.vim	     edit files over a network and browse (remote) directories
rrhelper.vim	     used for --remote-wait editing
spellfile.vim	     download a spellfile when it's missing
tarPlugin.vim	     edit (compressed) tar files
tohtml.vim	     convert a file with syntax highlighting to HTML
vimballPlugin.vim    create and unpack .vba files
zipPlugin.vim	     edit zip archives

Note: the explorer.vim plugin is no longer here, the netrw.vim plugin has
taken over browsing directories (also for remote directories).