The maintainer also removed the link from the installation documentation as well.
Quite recently, the maintainer of Yattee addressed in a GitHub issue why the app no longer on the App Store.
App is gone from the App Store because the last approved build was heavily outdated and not working so I removed it. I really hope it will be possible to bring the new version back to the App Store but cannot promise anything. I plan to continue updating it no matter if it is approved or not.
We’re most likely going to move forward with removing Yattee due to community members voicing their feedback about the app’s issues throughout a long period of time, so I’ll close this topic and continue the discussion in