What does this icon mean when debugging? Can there a be a tooltip on hover saying what it means?

is that the same one that appears here: https://www.jetbrains.com/help/img/idea/2019.3/debug_tutorial_tool_overview.png (line 4?) via: https://www.jetbrains.com/help/idea/debugging-your-first-java-application.html#analyzing-state

here's a "table" of sorts: https://www.jetbrains.com/help/idea/using-breakpoints.html#breakpoint-icons

may be it's "verified line breakpoint"?

Ah yes, that's it!

That is a very helpful table.

Given the number of icons that can show, it really seems like there should be a hover tooltip on that. It's quite unlikely I'm going to remember all 30 icons.

indeed!

Yes, that would be good. It’s an IntelliJ thing rather than a Cursive thing, though.