$ git clone -n https://src.fedoraproject.org/rpms/libisoburn.git /var/lib/mock/f40-build-800275-142890/root/chroot_tmpdir/scmroot/libisoburn
Cloning into '/var/lib/mock/f40-build-800275-142890/root/chroot_tmpdir/scmroot/libisoburn'...
$ git fetch origin de9dafd3df2d1ca80591c8ccd3a935ebc336176c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libisoburn
 * [new ref]         de9dafd3df2d1ca80591c8ccd3a935ebc336176c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at de9dafd Tightened run-time dependency for libburn/libisofs (#2222614)