$ git clone -n https://src.fedoraproject.org/rpms/qt5-qtbase.git /var/lib/mock/f42-build-862656-170997/root/chroot_tmpdir/scmroot/qt5-qtbase
Cloning into '/var/lib/mock/f42-build-862656-170997/root/chroot_tmpdir/scmroot/qt5-qtbase'...
$ git fetch origin c4bd1cc3ae724b1c20f38e2a27c40c4ffc274dd0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/qt5-qtbase
 * [new ref]         c4bd1cc3ae724b1c20f38e2a27c40c4ffc274dd0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c4bd1cc Obsolete QGnomePlatform and AdwaitaQt