$ git clone -n https://src.fedoraproject.org/rpms/xmlstreambuffer.git /var/lib/mock/f40-build-2191622-51450/root/chroot_tmpdir/scmroot/xmlstreambuffer
Cloning into '/var/lib/mock/f40-build-2191622-51450/root/chroot_tmpdir/scmroot/xmlstreambuffer'...
$ git fetch origin 274891c50fc670707b755c3557dbaaf540b2debe:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xmlstreambuffer
 * [new ref]         274891c50fc670707b755c3557dbaaf540b2debe -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 274891c Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild