$ git clone -n https://src.fedoraproject.org/rpms/rubygem-cookiejar.git /var/lib/mock/f45-build-34872-692/root/chroot_tmpdir/scmroot/rubygem-cookiejar
Cloning into '/var/lib/mock/f45-build-34872-692/root/chroot_tmpdir/scmroot/rubygem-cookiejar'...
$ git fetch origin 9bb92a0682a402e5f91ac5b9fffcb192d0b3b03d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-cookiejar
 * [new ref]         9bb92a0682a402e5f91ac5b9fffcb192d0b3b03d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9bb92a0 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild