Kris said that for now, he prefers – at this hectic early stage of Marvin 3 release – for us to submit bug reports by email to
hello@appstafarian.com, if possible.
Later on, I hope we can again use
Marvin's GitHub – that is the efficient and
transparent way of tracking bug reports and feature requests and their resolutions.

(Certainly not chaotic Facebook and not these MobileRead forums, either, which are only slightly less chaotic.)