$ git clone -n https://src.fedoraproject.org/rpms/librsvg2.git /var/lib/mock/f40-build-2008296-45361/root/chroot_tmpdir/scmroot/librsvg2
Cloning into '/var/lib/mock/f40-build-2008296-45361/root/chroot_tmpdir/scmroot/librsvg2'...
$ git fetch origin 22512cbd61527fb599dc8d17cf1a19d851697959:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/librsvg2
 * [new ref]         22512cbd61527fb599dc8d17cf1a19d851697959 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 22512cb Fix RHEL build