What is the meaning of blue triangle icon in Eclipse Package Explorer view?

Issue

Can someone please point me to where one can get more understanding on the meaning of the blue triangle icons in Eclipse and its derivatives (STS, etc.) and possibly modifying them:

Thank you.

Solution

In this case it means a default/package-protected class, much like how @greg-449 recognized its use with default/package-protected members.

Answered By - nitind