$ git clone -n https://src.fedoraproject.org/rpms/libjcat.git /var/lib/mock/f42-build-883601-185356/root/chroot_tmpdir/scmroot/libjcat
Cloning into '/var/lib/mock/f42-build-883601-185356/root/chroot_tmpdir/scmroot/libjcat'...
$ git fetch origin 9dccd3515cb18ddf48f4a836c64a6fe860b233e5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libjcat
 * [new ref]         9dccd3515cb18ddf48f4a836c64a6fe860b233e5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9dccd35 New upstream release, harder