$ git clone -n https://src.fedoraproject.org/rpms/fedora-messaging.git /var/lib/mock/f40-build-2262561-54509/root/chroot_tmpdir/scmroot/fedora-messaging
Cloning into '/var/lib/mock/f40-build-2262561-54509/root/chroot_tmpdir/scmroot/fedora-messaging'...
$ git fetch origin 8998b22ef8c5dfa987a33df04a8d84bb729e4e3e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fedora-messaging
 * [new ref]         8998b22ef8c5dfa987a33df04a8d84bb729e4e3e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8998b22 Modernize the spec file