$ git clone -n https://src.fedoraproject.org/rpms/chromium.git /var/lib/mock/f39-build-2010050-45484/root/chroot_tmpdir/scmroot/chromium
Cloning into '/var/lib/mock/f39-build-2010050-45484/root/chroot_tmpdir/scmroot/chromium'...
$ git fetch origin 235c5e38dceb73cfc42f63efd7e2e47ec010818b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/chromium
 * [new ref]         235c5e38dceb73cfc42f63efd7e2e47ec010818b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 235c5e3 update to 120.0.6099.71