What are the white blank areas midship starboard on Encore/Ovation & portside others

They extend from top to bottom on the ship and are in a prime real estate area so must be important!

They are portside on the other ships!

On the O class ships port side - located between e.g. suites 636 and 638 or on deck 7 between suites 734 and 732 - those are crew stairwells. Depending on suite location some guests go to muster drill via that staircase.

Haven't been on Encore but would assume they're the same.