$ git clone -n https://src.fedoraproject.org/rpms/rubygem-gdk4.git /var/lib/mock/f39-build-1502441-34919/root/chroot_tmpdir/scmroot/rubygem-gdk4
Cloning into '/var/lib/mock/f39-build-1502441-34919/root/chroot_tmpdir/scmroot/rubygem-gdk4'...
$ git fetch origin ba95e05e439e7ee96913df8dd283c57602f528e6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-gdk4
 * [new ref]         ba95e05e439e7ee96913df8dd283c57602f528e6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ba95e05 4.2.0 entry