$ git clone -n https://src.fedoraproject.org/rpms/jasper.git /var/lib/mock/f40-build-802794-144103/root/chroot_tmpdir/scmroot/jasper
Cloning into '/var/lib/mock/f40-build-802794-144103/root/chroot_tmpdir/scmroot/jasper'...
$ git fetch origin 4e387a6b1abf77f8987d6be8debd2029996253a7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jasper
 * [new ref]         4e387a6b1abf77f8987d6be8debd2029996253a7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4e387a6 Resolves: #2265201 - new upstream release 4.2.1