Wotc should change how colorless works in brawl.

I'd say "mana identity" somewhat exists in commanded, due to rule 903.5d. That's why they need the exception in 903.12:

https://www.reddit.com/r/MagicArena/comments/hhy9oo/wotc_should_change_how_colorless_works_in_brawl/fwcy7e5?utm_source=share&utm_medium=web2x

https://mtg.gamepedia.com/Commander_(format))

903.5d A card with a basic land type may be included in a Commander deck only if each color of mana it could produce is included in the commander’s color identity.

/r/MagicArena Thread Parent