What represent this pharo classes icons?

Question

I'm seeing different icons for different classes, like in this picture:

What does it mean? Some of them, with a red icon let me add comments, but the ones with a "c" and a "ray" for example, dont allow me.

The comments mention something about Class Responsibility Collaborator (CRC) design, but it is not clear how comments affect the icon.

Answer 1

the exclamation mark shows that class has no comment. Lightning is for Exception classes, text bubbles for Announcement. Icons with braces are for collections and the ones with capital sigma (Σ) are for magnitude classes (e.g. numbers).

Icons with C are for generic classes, icons with T are for traits.

There are also classes with a small gray/green/red circle. They show that methods of this class have a test associated with them, and can show if all test pass (green) or not (red). Clicking on an icon like this will run all the tests associates with class's methods