2014-09-20 : Mardu Warshrieker’s raid ability isn’t a mana ability even though it adds mana to your mana pool. It uses the stack and can be responded to.

2018-01-19 : Raid abilities care only that you attacked with a creature. It doesn’t matter how many creatures you attacked with, or which opponent or planeswalker controlled by an opponent those creatures attacked.

2018-01-19 : Raid abilities evaluate the entire turn to see if you attacked with a creature. That creature doesn’t have to still be on the battlefield. Similarly, the player or planeswalker it attacked doesn’t have to still be in the game or on the battlefield, respectively.