$ git clone -n https://src.fedoraproject.org/rpms/gtk3.git /var/lib/mock/f39-build-2296798-56402/root/chroot_tmpdir/scmroot/gtk3
Cloning into '/var/lib/mock/f39-build-2296798-56402/root/chroot_tmpdir/scmroot/gtk3'...
$ git fetch origin 4960b4fb8b45350a35bd202d177d8df0cada5e89:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gtk3
 * [new ref]         4960b4fb8b45350a35bd202d177d8df0cada5e89 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4960b4f Update to 3.24.41