Delphi introduced the .groupproj files to support MSBUILD.
I couldn’t find an XSD for it, but need to do some fiddling with those files, so I created one. It’s not very detailed, I think it gets most of the definition right.
The checkin is on my BeSharp.net mercurial repository on BitBucket:
–jeroen
via: jeroenp / BeSharp.net / commit / c122bbdef42e — Bitbucket.