$ git clone -n https://src.fedoraproject.org/rpms/z3.git /var/lib/mock/f42-build-side-1-3584174-46892/root/chroot_tmpdir/scmroot/z3
Cloning into '/var/lib/mock/f42-build-side-1-3584174-46892/root/chroot_tmpdir/scmroot/z3'...
$ git fetch origin 23bd2e8fcae087be3f3ec49ae15d5b2263a438e7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/z3
 * [new ref]         23bd2e8fcae087be3f3ec49ae15d5b2263a438e7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 23bd2e8 Version 4.15.2