On some platforms it's expected that Perl already exists, and this would be called "system Perl", for lack of a better description. Windows doesn't ship with Perl, and there are competing standards when Perl is actually explicitly installed (ActiveState, Strawberry, and others), each of which would install to a different path.

When a vendor ships an app that requires Perl into an environment where Perl isn't a standard component, he will often ship Perl alongside the app. This is the only way to guarantee that the toolchain is complete, particularly on platforms such as Windows where more often than not the toolchain is incomplete otherwise. This version should be considered a sort of "system perl"; one that shouldn't be tampered with if you want the apps that depend on it to continue to work. Git does this. Oracle does this. cygwin does this.

Just forget about the git Perl, and the Oracle Perl. For your own work, install one of the explicitly installed versions (ActiveState or Strawberry, for example), set your path accordingly, and get to work.