$ git clone -n https://src.fedoraproject.org/rpms/xz-java.git /var/lib/mock/f40-build-2648563-66790/root/chroot_tmpdir/scmroot/xz-java
Cloning into '/var/lib/mock/f40-build-2648563-66790/root/chroot_tmpdir/scmroot/xz-java'...
$ git fetch origin b1288ded18b006eed707e523a7796e96408c42f6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xz-java
 * [new ref]         b1288ded18b006eed707e523a7796e96408c42f6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b1288de Rebuilt for java-21-openjdk as system jdk