Mark unvisited rooms

[fratus666]

Added in news 2716

• The GMCP Room.Known module was added. It lets your client fetch information
  about which rooms your character is aware of.

Would this be a way to show rooms a character has never visited?

[Sunnyl75]

Is it known if this compares a room against the known rooms to verify?
It might be able to be leveraged to create a hotmap of where you’ve journeyed in each session