$ git clone -n https://src.fedoraproject.org/rpms/thunderbird.git /var/lib/mock/f38-build-side-42-init-devel-696687-27003/root/chroot_tmpdir/scmroot/thunderbird
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-696687-27003/root/chroot_tmpdir/scmroot/thunderbird'...
$ git fetch origin 618f3cf723acad4b1cfd47d980d2bf9b9f6934a6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/thunderbird
 * [new ref]         618f3cf723acad4b1cfd47d980d2bf9b9f6934a6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 618f3cf Update to 102.9.1