GTFS feeds are the backbone of public transit data - but actually seeing what's inside one has always been far harder than it should be.
The old workflow usually went something like: unzip the feed, write a script to parse routes.txt and stops.txt, spin up QGIS or another GIS tool, load the shapes, and spend 20 minutes configuring things - just to answer a basic question like "do these two routes actually overlap here?" That's a lot of friction for what should be a 10-second sanity check.