$ git clone -n https://src.fedoraproject.org/rpms/jboss-jaxrs-2.0-api.git /var/lib/mock/f40-build-2376231-60422/root/chroot_tmpdir/scmroot/jboss-jaxrs-2.0-api
Cloning into '/var/lib/mock/f40-build-2376231-60422/root/chroot_tmpdir/scmroot/jboss-jaxrs-2.0-api'...
$ git fetch origin f1a028dec7d7ca94017a27ec9d756970ae523603:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jboss-jaxrs-2.0-api
 * [new ref]         f1a028dec7d7ca94017a27ec9d756970ae523603 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f1a028d Conditionalize arches for RHEL