It's on the PTR, and it's being datamined, which is why you're not seeing it on battle.net anywhere yet. They don't push the patch notes at the same time they push the PTR updates, so we often datamine things before they publish the patch notes on them (which, of course, is WHY we datamine, in the first place).
either way it still is discouraging. in a nutshell it forcasts that mana regen is going to scale into rediculous levels and everything will soon become about throughput. while mana shouldn't be a problem in the final tier of an expansion, it shouldn't however be infinite.
I think we might see a complete revamp of of some healers in the next expansion.
Such is the risks of datamining. Sometimes, we get the drop on a new change. Sometimes, we snag a tooltip fix that doesn't reflect an actual change. Which is why I always say to take datamined changes with a grain of salt.