I don't understand the new mana rules for EDH. Could you explain them please?
Here’s the best way I can explain it: If something would add mana to your mana pool, that mana is added to your mana pool. It doesn’t matter anymore if the color of the mana is within your commander’s color identity or not.
Previously mana of colors outside of your commander’s color identity would be added to your mana pool as colorless mana instead. This is no longer the case. There is no longer a special rule for mana being added to your mana pool in Commander / EDH.
For example: I control Birds of Paradise and my commander is Nissa, Vastwood Seer whose color identity is mono-green. I tap my Birds of Paradise for mana and choose black as the color, so one black mana is added to my mana pool.
There is no change to what cards are allowed in decks, though. I still can’t play Noble Hierarch or Rattleclaw Mystic in that Nissa deck because they have mana symbols in their text (and thus their color identity) outside of Nissa’s color identity. The change will only matter for “add mana of any color” effects or for cards owned by other players that you gain control of. (And probably for some weird stuff from other casual formats like Planechase, Archenemy, etc.)
