$ git clone -n https://src.fedoraproject.org/rpms/rubygem-gobject-introspection.git /var/lib/mock/f41-build-808644-145985/root/chroot_tmpdir/scmroot/rubygem-gobject-introspection
Cloning into '/var/lib/mock/f41-build-808644-145985/root/chroot_tmpdir/scmroot/rubygem-gobject-introspection'...
$ git fetch origin ba8cf544cd564a7fc9a45b22e4c21c938313b9dc:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-gobject-introspection
 * [new ref]         ba8cf544cd564a7fc9a45b22e4c21c938313b9dc -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ba8cf54 4.2.2 entry