$ git clone -n https://src.fedoraproject.org/rpms/rr.git /var/lib/mock/f39-build-1925469-43033/root/chroot_tmpdir/scmroot/rr
Cloning into '/var/lib/mock/f39-build-1925469-43033/root/chroot_tmpdir/scmroot/rr'...
$ git fetch origin 8e6bbaf467bcc984ba853049f04000d9e672c709:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rr
 * [new ref]         8e6bbaf467bcc984ba853049f04000d9e672c709 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8e6bbaf Rebuild for capnproto 1.0.1