$ git clone -n https://src.fedoraproject.org/rpms/rubygem-gobject-introspection.git /var/lib/mock/f40-build-733952-105596/root/chroot_tmpdir/scmroot/rubygem-gobject-introspection
Cloning into '/var/lib/mock/f40-build-733952-105596/root/chroot_tmpdir/scmroot/rubygem-gobject-introspection'...
$ git fetch origin 239d910a751c59024194514f3537e97219312973:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-gobject-introspection
 * [new ref]         239d910a751c59024194514f3537e97219312973 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 239d910 4.2.0 entry