$ git clone -n https://src.fedoraproject.org/rpms/libgsf.git /var/lib/mock/f39-build-1457611-33006/root/chroot_tmpdir/scmroot/libgsf
Cloning into '/var/lib/mock/f39-build-1457611-33006/root/chroot_tmpdir/scmroot/libgsf'...
$ git fetch origin c1de5acad28f3dba2f3056b5eed55657775b9ba5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libgsf
 * [new ref]         c1de5acad28f3dba2f3056b5eed55657775b9ba5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c1de5ac Add MinGW packages