Android Question Underline color in Modules tab?

[Sandman]

I have a couple of underlined modules with different colors, and I can't for the life of me find any info in the forum about how to understand that. I'm sure I've missed something obvious and can't find the optimal search terms, can somebody point me to a post with info how to interpret them?

 

[agraham]

A purple underline means the module has warnings, a red underline means it contains an error - there may be others that I haven't encountered.

 

[Sandman]

Aha, the red one makes sense. I would probably had understood it intuitively if the purple one was orange instead. Thanks!