[Baxxter]

Is the dashed blue line their intended route, or what they would submit to ATC? Differs quite a bit from the actual flight.

[titanomachy]

Looks like it could be the same as the actual route but sampled at a lower resolution.

[Philip-J-Fry]

In the layers (button top right) it's called the "planned route".

[stevehawk]

It's usually the filed flight plan (for instrument flights)