Why use `after/plugin` dir for sources ?

[leath-dub]

I didn't want raise this issue in nvim-cmp as it is actually not related to that plugin, more how the sources by @hrsh7th use the after/plugin dir. The problem is that this directory is not something you should use if you expect to allow a plugin be hot loaded, i.e. added to the runtimepath dynamically: for example via packadd.

See this issue https://github.com/vim/vim/issues/1994. after/plugin is not loaded by the builtin package manager and as suggested by a contributor in that issue, this is a directory primarily for users not plugins.