$ git clone -n https://src.fedoraproject.org/rpms/boom-boot.git /var/lib/mock/f39-build-1530849-36198/root/chroot_tmpdir/scmroot/boom-boot
Cloning into '/var/lib/mock/f39-build-1530849-36198/root/chroot_tmpdir/scmroot/boom-boot'...
$ git fetch origin 960309e0c08399df4f4deaf9112b4badfa009680:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/boom-boot
 * [new ref]         960309e0c08399df4f4deaf9112b4badfa009680 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 960309e Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild