Thank you all for your answers.
1. But I mean subscriptions like this "debian-user":) But I really like your answers about Debian's freedom. I think it is useful information. Thanks.
2. I just have verified GPG's keys manually:
https://keyring.debian.org/ 2.1. I have downloaded SHA512 SUMS.sign SHA512SUMS from
https://cdimage.debian.org/debian-cd/current/amd64/bt-cd/ 2.2. I have done then: gpg --keyserver
keyring.debian.org --verify SHA512SUMS.sign SHA512SUMS
2.3. Then I have got next info: Signed was made in 30 june 2024
And RSA key: DF9B9C49EAA9298432589D76DA87E80D6294BE9B
I have compared 2011 's key and mine and they are the same.
But is it a good idea to do that? Or do I need to download the open key and then compare them?
And is verification with SHA512SUMS.sign and SHA512SUMS enough? Should I do the same actions with SHA216SUMS.sign and SHA216SUMS?