$ git clone -n https://src.fedoraproject.org/rpms/qt5-qtwebengine.git /var/lib/mock/f42-build-3450948-45482/root/chroot_tmpdir/scmroot/qt5-qtwebengine
Cloning into '/var/lib/mock/f42-build-3450948-45482/root/chroot_tmpdir/scmroot/qt5-qtwebengine'...
$ git fetch origin 2823a4df8c81befb1c42e51aa393aef55c42e5a8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/qt5-qtwebengine
 * [new ref]         2823a4df8c81befb1c42e51aa393aef55c42e5a8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2823a4d Switch to ld.bfd