This issue is for discussion of the map viewer use case “Display custom web content describing map features”, its examples & list of required capabilities.

This section is currently a placeholder. It may be worth splitting it in two: one for pop-up/tooltip annotations, and one for annotations (legends, data figures, ???) displayed directly in the map layer. Or we can consider this one use case, but multiple capabilities/technological approaches to fulfill it.

There is some overlap with #2, although I'm still not quite certain about how to frame that idea.