$ git clone -n https://src.fedoraproject.org/rpms/xstream.git /var/lib/mock/f40-build-2603709-63346/root/chroot_tmpdir/scmroot/xstream
Cloning into '/var/lib/mock/f40-build-2603709-63346/root/chroot_tmpdir/scmroot/xstream'...
$ git fetch origin 0b0b813b73e93e2cab0f8c876fc6c25ae512edbc:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xstream
 * [new ref]         0b0b813b73e93e2cab0f8c876fc6c25ae512edbc -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0b0b813 Rebuilt for java-21-openjdk as system jdk