Plugins are loaded using built-in Vim 8 package manager. Each external plugin is managed via git submodules.
For example, to install a new plugin we'd clone it like so:
git submodule add https://github.com/natebosch/vim-lsc pack/plugins/start/vim-lsc
If we later want to remove a plugin:
git submodule deinit -f -- pack/plugins/start/vim-lsc
rm -rf .git/modules/pack/plugins/start/vim-lsc
git rm -rf pack/plugins/start/vim-lsc