$ git clone -n https://src.fedoraproject.org/rpms/chromium.git /var/lib/mock/f38-build-side-42-init-devel-631652-26379/root/chroot_tmpdir/scmroot/chromium
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-631652-26379/root/chroot_tmpdir/scmroot/chromium'...
$ git fetch origin 8d7d7962cb0978ed3f5e9a729a21063272315ef3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/chromium
 * [new ref]         8d7d7962cb0978ed3f5e9a729a21063272315ef3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8d7d796 move disable-features and enable-features flags to config file