Hello,
Thank you for the detailed description. We'll check it.
I'll provide you with more info as soon as I can.

Any progress?

If you open the freedownloadmanager.deb package as an archive and look into control.tar.xz > ./postinst, you will find something looks like:

[code]
/usr/bin/apt-key add - >/dev/null 2>&1 <<PUBKEYDATA
-----BEGIN PGP PUBLIC KEY BLOCK-----
...
-----END PGP PUBLIC KEY BLOCK-----
PUBKEYDATA
[/code]

The above script uses `apt-key` to add the public key. As far as I know, we should copy that key to `/etc/apt/trusted.gpg.d` instead of using `apt-key add`. For example:

[code]
/usr/bin/gpg --dearmor --output /etc/apt/trusted.gpg.d/freedownloadmanager.gpg >/dev/null 2>&1 <<PUBKEYDATA
-----BEGIN PGP PUBLIC KEY BLOCK-----
...
-----END PGP PUBLIC KEY BLOCK-----
PUBKEYDATA
[/code]

I'm not sure how the .deb package are packaged manually or automatically. But I feel this is not a very difficult problem to solve.

BTW, another more general distribution method is to package the application as an AppImage (though I'm not very familiar with it), which will enable FDM to run on almost all Linux distributions, not just Debian-based distros.

Hello,
I'm not a Linux expert. Could you please provide more details? For now, I don't even know what you're talking about :)

We should copy the keyring file to trusted.gpg.d ( or use the `install` command from coreutils ) instead.

The Linux deb package still uses [code]apt-key add[/code] to add keyring files. However, apt-key is deprecated. Keyring files should be managed in trusted.gpg.d instead (see apt-key(8)).