$ git clone -n https://src.fedoraproject.org/rpms/jackson-jaxrs-providers.git /var/lib/mock/f40-build-2370686-60393/root/chroot_tmpdir/scmroot/jackson-jaxrs-providers
Cloning into '/var/lib/mock/f40-build-2370686-60393/root/chroot_tmpdir/scmroot/jackson-jaxrs-providers'...
$ git fetch origin db26287ea37c6e4c285436e9a82a873a2b427a05:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jackson-jaxrs-providers
 * [new ref]         db26287ea37c6e4c285436e9a82a873a2b427a05 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at db26287 Conditionalize arches for RHEL