question on passive tree "notable" nodes

I'm new to using PoB, and noticed when hovering over "notable" nodes (like "Retribution" just northwest of the Templar starting spot), the tooltip shows "clear crimson crimson" next to the node name. I think those are jewels, but I don't see a way to socket a jewel in that node, so I'm trying to figure out why PoB is showing that info there.

Wonderful, thanks!

I have learned a metric ton of stuff in the 1 week I've been playing PoE, and have to admit, I haven't even heard of oils yet!!

Wow, is there a lot to learn in this game :)

^I have 15000 hours in this game across 12 years....I'm still learning things. You are going to keep discovering more and more and more and more. Enjoy it! Best part of PoE