$ git clone -n https://src.fedoraproject.org/rpms/qt5-qtwebengine.git /var/lib/mock/f42-build-side-1-3589372-46998/root/chroot_tmpdir/scmroot/qt5-qtwebengine
Cloning into '/var/lib/mock/f42-build-side-1-3589372-46998/root/chroot_tmpdir/scmroot/qt5-qtwebengine'...
$ git fetch origin 7c85dd75044ac679f80d47c32ee046be0152b862:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/qt5-qtwebengine
 * [new ref]         7c85dd75044ac679f80d47c32ee046be0152b862 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7c85dd7 Rebuild (qt5)