$ git clone -n https://src.fedoraproject.org/rpms/rust-custom_error.git /var/lib/mock/f39-build-1455311-32915/root/chroot_tmpdir/scmroot/rust-custom_error
Cloning into '/var/lib/mock/f39-build-1455311-32915/root/chroot_tmpdir/scmroot/rust-custom_error'...
$ git fetch origin ddbec06a1b47f439aeb9af82724c233a08b9139c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-custom_error
 * [new ref]         ddbec06a1b47f439aeb9af82724c233a08b9139c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ddbec06 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild