What's included:
All of CEDET
All files in emacs-lisp
Most if not all files in tramp/mail/net
Everything in progmode that doesn't depend on an external utility (namely moz) being installed
Any TeX or reference/citation functionality (reftex, bibtex, bibliography, citar, citeproc)
Icon/emoji/image support (e.g alltheicons, major-mode-icons)
All completion and widening/narrowing libraries - helm, ivy, counsel, company, auto-complete,
Perspective, window-purpose, and similar
Evil packages
Treemacs
Many other miscellaneous packages I'm forgetting.