I've been working for the past week on a new kbin app. At the moment, it's just a prototype and only the "Feed" view has content (you can't sign into an account or post anything yet); you can see threads, thread images, thread comments, thread links, and thread votes/boosts. You can also change the "Theme Mode" and "Instance Host" in the settings.
Here's a link to the source code (contributions welcome for those that know flutter): github.com/jwr1/interstellar.
For testers, here are links to the first working builds: AppImage and APK.
The Mags tab shows mags but clicking them doesn't do anything
Changing Instance host to "kbin.social" gives me a "something went wrong" when I go back to the Feed tab. Also the magazines now give me the same "something went wrong"
The individual magazine's page has not been implemented yet; I might try to work on that tomorrow. Unfortunately, kbin.social does not support the API yet (that's why karab.in was the default).
I was using the flutter_markdown package to render markdown. Fortunately, the text style can be changed, so once I get around to it, I'll fix the color issue.