$ git clone -n https://src.fedoraproject.org/rpms/rust-cxxbridge-flags /var/lib/mock/f42-build-3433706-45428/root/chroot_tmpdir/scmroot/rust-cxxbridge-flags
Cloning into '/var/lib/mock/f42-build-3433706-45428/root/chroot_tmpdir/scmroot/rust-cxxbridge-flags'...
$ git fetch origin eaa8f30925cffdda97210a659fcbaba5b41c9708:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-cxxbridge-flags
 * [new ref]         eaa8f30925cffdda97210a659fcbaba5b41c9708 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at eaa8f30 Update to version 1.0.150 (rhbz#2346635)