For RPM packages, there is no separate signature. RPM packages have a built-in GPG signature and MD5 checksum. You can verify a package by running the following command:
$> rpm --checksig package_name.rpm
Example:
$> rpm --checksig mysql-community-server-8.0.40-1.el8.x86_64.rpm
mysql-community-server-8.0.40-1.el8.x86_64.rpm: digests signatures OK
If you are using RPM 4.1 and it complains about (GPG)
NOT OK (MISSING KEYS: GPG#3a79bd29)
, even though you
have imported the MySQL public build key into your own GPG
keyring, you need to import the key into the RPM keyring
first. RPM 4.1 no longer uses your personal GPG keyring (or
GPG itself). Rather, RPM maintains a separate keyring because
it is a system-wide application and a user's GPG public
keyring is a user-specific file. To import the MySQL public
key into the RPM keyring, first obtain the key, then use
rpm --import to import the key. For
example:
$> gpg --export -a 3a79bd29 > 3a79bd29.asc
$> rpm --import 3a79bd29.asc
Alternatively, rpm also supports loading the key directly from a URL:
$> rpm --import https://repo.mysql.com/RPM-GPG-KEY-mysql-2022
You can also obtain the MySQL public key from this manual page: Section 2.4.2, “Signature Checking Using GnuPG”.