SpamAssassin Rule: ALL_TRUSTED
Standard description: Passed through trusted hosts only via SMTP
"Trusted" does not mean "trusted to not send spam." It means "trusted to not forge Received: headers."
If your message hits on the ALL_TRUSTED rule, it means that all of the Received: headers in the message were inserted by SMTP relays you have indicated are "TrustedRelays" and the "from" part of the Received: header is also from one of your "TrustedRelays"; consequently, no tests of the source of the message (for example, tests against DNSBlocklists) will be performed.
The default scores for this rule can be found in the online list of tests.