What does the red exclamation point icon in Eclipse mean? (Icon is on right, not left)

Question

What does the red exclamation point icon in Eclipse mean? There are lots of different search results on the Internet about "red exclamation point icons" and "red exclamation mark decorators" and "red bang icons", including many on this site but the one I have on my project is on the right and not the left which everyone seems to be talking about which I think are related to build path errors. So, to be clear, this is the one I mean:

screenshot of red exclamation point icon

It appears as a decorator on projects in the Package Explorer view. The project is a Maven project using GWT. I was trying to change the pom file and did a maven install and then the icons showed up. I undid all the changes and then tried to do a clean / install and they don't seem to go away now. The problems tab is empty and I can run the project so I don't think there are any build path errors.

Answer 1

It means there are build path problems on the project. See What do the icons in Eclipse mean? for details about the various icons (and icon decorators) in Eclipse.