Swiftlint: What is the purpose of opt_in_rules?

[castus]

I know that this question might by stupid, but I don't get the idea behind opt_in_rules. Can someone explain me what is the purpose of opt_in_rules?
Thanks

[marcelofabri]

opt_in_rules are disabled by default (you have to explicitly add them on your configuration file).

From what I've seen there're a few reasons on why a rule should be opt-in:

• A rule that can have many false positives (empty_count)
• A rule that is too slow
• A rule that is not general consensus or only useful in some cases (force_unwrapping, missing_docs)

[jpsim]

That's exactly right.

[castus]

Thank you for such a good answer!