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A ruleset in the "extra" set would have different criteria.
- DanielQuinlan suggested: The second, a collection that do not qualify for rules/core. For example, SpamAssassin intentionally doesn't filter virus bounces (yet, at least), but there is a good virus bounce ruleset out there.
- BobMenschel: Similarly, an "extra" rules set might include rules that positively identify spam from spamware, but hit <0.25% of spam. Or an "aggressive" rules set might include rules that hit with an S/O of only 0.89, but push a lot of spam over the 5.0 threshold without impacting significantly on ham.
We can also vote for extraordinary stuff that doesn't fit into those criteria...
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