I created both my morning commute and afternoon commute in RWGPS, and saved them as GPX files. I could not choose to save on the eTrex, so I saved to my computer and copied them into the GPX folder on the Garmin. One shows up in Routes; the other in Tracks. Not really sure why.
There are two types of GPX files:
track files and
route files. (There's kind of a third type: waypoint files.)
Track files have enough points to trace the curves and turns of your intended path. On the Edges (at least), the "fancy" navigation follows the track (as best it can). Track files originally were recorded tracks. That sort still exists but things like RWGPS create synthetic ones.
Route files have a few points (waypoints) that indicate the places you must pass through. With route files, the device has to calculate the route ("fancy" navigation) between the waypoints. (The Edges can't use route files at all.)
It's a bit confusing because "route" is also used generically. For example, you create a route in RWGPS but can create a track GPX file and a route GPX file from it.
I suspect the files are in two lists because you chose different export options in RWGP (track for one and route for the other).