Under the silver cover is the flat field corrector.
The ATC-02C control unit (an optional extra) is the compact version (hence the "C") and it's built into the telescope (at about the 5 o'clock position in this picture). So there are no unsightly boxes attached to the outside.
All aspects of the scope (fans, primary and secondary dew heaters and secondary focusser) are controlled via the ATC. I didn't bother with the hand controller because it will be an observatory scope under computer control.