For who ever will look at this topic, I finally got a direct answer from Adobe. Following is the direct link which explains the meaning of the color fx badges:
Apply, remove, find, and organize clips in Premiere Pro
FX badges
An FX badge is an icon in the Timeline that lets you easily identify if an effect has been applied to a clip.
Premiere Pro offers FX badges in different colors. Just by looking at the badge color, you can determine if you have applied an effect, modified an intrinsic effect, and so on.
A. Gray FX badge B. Purple FX badge C. Yellow FX badge D. Green FX badge

| FX badge color | Denotes |
| Gray | No effect applied (default badge color) |
| Purple | Non-intrinsic effect applied (like, color correction, blur) |
| Yellow | Intrinsic effect modified (like, position, scale, opacity) |
| Green | Intrinsic effect modified and additional effect applied |
| Red underline | Master Clip effect applied |
So Ann was close with her answer but not as specific as what it actually is! ;-)
David