An existing NetPath probe is examined, and it is noted that the thickness of connection...

Comprehensive and Detailed Explanation From Exact Extract:

In NetPath visualizations, the thickness of the connection lines represents the likelihood or frequency of traffic using that path.

From the documentation:

“In NetPath, thicker lines between nodes indicate a higher probability that traffic will flow along that path. This visualization is based on the frequency of successful probes and actual traffic analysis.”