The gamerule 'mobGriefing' now has an alternate gamerule argument called 'doMobGriefing', which doesn't do anything (but implies it should change the same gamerule).

I found this while I was trying to disable mob griefing (obviously), but I typed 'doMobGriefing' intead by accident and ended up with several craters. Later, I realized my mistake, as well as how it actually DID change a gamerule for the first time (I've accidentally messed this up before).

I tested 'doMobGriefing' against 'mobGriefing' with creepers, withers, blazes, and villagers. 'doMobGriefing' did absolutely nothing to stop the mobs from changing the terrain, while 'mobGriefing' worked every time, as was expected.

EDIT:
Never mind, it seems you can enter custom gamerules although it doesn't actually say something logical like "New game rule created" or anything of the sort. And can someone help me close this?