$ git clone -n https://src.fedoraproject.org/rpms/yelp-tools.git /var/lib/mock/f45-build-39268-733/root/chroot_tmpdir/scmroot/yelp-tools
Cloning into '/var/lib/mock/f45-build-39268-733/root/chroot_tmpdir/scmroot/yelp-tools'...
$ git fetch origin f81f85274993c973e46ac5424212d29ac9baf53a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/yelp-tools
 * [new ref]         f81f85274993c973e46ac5424212d29ac9baf53a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f81f852 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild