Your question doesn't have much in the way of detail, so it's hard to address. However, the "green line" area that you have pictured is the standard "selected feature" highlighting.
What that shows you is that the feature you've clicked on has the shape of the green line. That doesn't tell you what those lines are, however, or anything about the yellow lines at all.
The Esri Community is a good place to come with questions, but this sort of question is one that can only be definitively answered by whomever has produced the map you're looking at.
- Josh Carlson
Kendall County GIS
