wojon is that app trustworthy enough to use it with GOS?
Quickly looking at the app's Github repository, it does appear they're really getting releases from Github. I didn't check other app sources.
I haven't actually used Obtainium, but I plan to eventually. Based on the code I checked it looks trustworthy to me.
wojon Also, the app description says that installs happen asynchronously. What does that mean exactly and did you run into problems with GOS?
Based on what they said in the readme and a comment in the code it just means that they can't follow the status of the install. Looking at the Flutter plugin they're using it's true there's no code to wait and see if the app installs successfully, just if the OS accepts the install request and prompts the user.
This shouldn't cause anyone any problems as far as I can tell. If there's a problem, the app just won't install and the OS will notify you of the reason. When you relaunch Obtanium, it'll scan your installed apps again so if the install failed, you can try again.