Due to some UI issues with the normal theme (see this question) I switched to the dark theme by setting gtk-application-prefer-dark-theme=1 in ~/.config/gtk-3.0/settings.ini. In general this works just fine, but there are some minor glitches like the selection color for multiple items.
So my question is: Is the dark theme officially supported and is it worth reporting bugs related to it?
No, the dark theme is not officially supported. It can be installed manually, as you did, or through elementary-tweaks (which is doubly unsupported by the devs). I tested the dark theme for a few days, but found that only a few apps actually supported the theme and the rest did their own thing.
This doesn't mean that app maintainers won't take bug reports on making their apps work better across themes, but the devs certainly don't have dark theme use cases in mind when shipping the main OS. As a rule, if it isn't in the main Settings and it isn't a feature request, it's likely not within the purview of the small dev team. (I personally don't think it would be a bad feature to have, so perhaps you'd like to join in?)
