F-Droid is an installable catalogue of FOSS (Free and Open Source Software) applications for the Android platform. The client makes it easy to browse, install, and keep track of updates on your device.
it's on the IzzyOnDroid repo, not the official one, hence the 404. when you use "share link" option in the official F-droid client, it will generate an F-droid repo URL based on the app's package name, regardless of whether the app is in that repo or not. here's the proper link:
Because not everyone agrees with each other on project directions or goals. In this case the developer is trying to learn something about flutter and dart while honing his coding skills. It's actually all explained in his git repo.
It feels wrong to see an ipa file in the github repo considering iOS users can't even sideload without some weird tinkering (until the EU mandate takes place).