What Exactly Do Commanders Do?

^ Title. What bonuses do commanders give when you check the 'commander' box in the unit editor? (Or when you create a unit whose type is commander). It's never really clear...

Also, can we edit these bonuses?

Also, how comes I seem to be unable to create commanders?

Bumping because everyone seems to be asking this and no one seems to know. For all we know commanders could be completely useless anyway.

Yes. i also asked a similar question a few days ago
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