$ git clone -n https://src.fedoraproject.org/rpms/libpar2.git /var/lib/mock/f45-build-16739-490/root/chroot_tmpdir/scmroot/libpar2
Cloning into '/var/lib/mock/f45-build-16739-490/root/chroot_tmpdir/scmroot/libpar2'...
$ git fetch origin c6c74e7df761ac8cee9ae14f3bc3b3eef9782ca9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libpar2
 * [new ref]         c6c74e7df761ac8cee9ae14f3bc3b3eef9782ca9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c6c74e7 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild