With Delphi 1, it was easy to choose what to put in your version control systems: basically .pas, .dfm, .dpr, .inc, .res, .cfg and you were set.
Now there are many more extensions involved, so it is harder to choose what to put in your version control system and what not.
The File Extensions of Files Generated by RAD Studio page helps you with that: it lists most of the Delphi file extensions (.local is a noticeable exception) that are used today.
–jeroen
via: File Extensions of Files Generated by RAD Studio – RAD Studio XE2.