Cellar advice

[6beachlover]

So we have a cellar one side dryer than the other side! I’ve been considering maybe having it done we have lights and electric already but I mean a full Reno, I’ve always just wondered what these squiggly lines are and what this stuff is on the walls? I tried google lens but couldn’t find any answers! TIA

Isn't it just old lime wash that got damp?

Possibly it was like this when we moved in so unsure but hoped someone might be able to answer my curiosity. I did wonder if it was lime wash, it just does sort of brush off when I touched the squiggly bit.