$ git clone -n https://src.fedoraproject.org/rpms/opencv.git /var/lib/mock/f40-build-2358631-60310/root/chroot_tmpdir/scmroot/opencv
Cloning into '/var/lib/mock/f40-build-2358631-60310/root/chroot_tmpdir/scmroot/opencv'...
$ git fetch origin 56850342e36ba66933c3c10b38a86bffc90d7781:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/opencv
 * [new ref]         56850342e36ba66933c3c10b38a86bffc90d7781 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5685034 Rebuild (tesseract)