Can't install RedScreenActivity by F-Droid Basic: TargetSdkVersion

RedScreenActivity (org.vi_server.red_screen) is not directly installable by F-Droid Basic: "TargetSdkVersion of apk file (0) is not the expected targetSdkVersion (3)!".

If I download the apk from f-droid.org and install manually, it installs and works (though shows a bit of compatibility warnings).

There is no TargetSdkVersion in the source code or apk file's manifest.

Is is something to be fixed upstream or in F-Droid itself?

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information