Hello
If you want the latest version of Electrum for example, you need to download the apk on the Electrum website (because the last version is not available on Play store).
So you need to check the PGP file signature of the apk to be sure there has not been any hack.
I do this by installing a shell terminal for Android(Termux) and the gpg package.
But it's not convenient to use a shell on a smartphone, and I don't think it's a suitable solution for beginners.

So are there apps on Android offering PGP file signature checking?

Thank you

Thank you
Yes I tried it before using Termux but I couldn't verify my file signature with it (the file signature of the electrum apk).
I don't know if I missed something but I wasn't able to do it with openkeychain while it worked with Termux...

Thank you but this tool only verifies if the signature belongs to the public key submitted.
It doesn't check if the signature matches the file I want to check (the apk).
And this is precisely what I want to be able to do conveniently : being sure the file is ok.

Moreover I get a bug with this tool
org.bouncycastle.openpgp.PGPSignatureList cannot be cast to org.bouncycastle.openpgp.PGPCompressedData