Delphi has used FPC only in XE2 for building iOS applications. After XE2 FPC is not used because Delphi has own compiler for mobile platforms (iOS, Android). Files "freepascal_" which you see it is a connectors generators for Datasnap servers so as users of FPC can use DataSnap Delphi Servers in own client applications. Analogous generators exist for Java, JavaScript, C# and Objective-C. And don't be naive - FPC cannot replace modern Delphi.