Calories on an e-bike are always an estimate. The motor does part of the work, and how much it does depends on the mode you ride in. Only a power meter or a heart-rate sensor can measure what you actually put in. A route planner can't, so TrailRunner asks you how much support you use.
Open the Personal section of the route inspector. For Biking, Road Biking and Mountain Biking its last row is E-bike assist: None, Light or Strong. The choice is made once per sport. It applies to every route of that sport and on all your devices.
The intensity values come from the 2024 Adult Compendium of Physical Activities, which lists e-bike riding with light support at 6.0 MET and with high support at 4.0 MET. An unassisted bike is 8 to 10 MET. An e-mountain bike is rated a little higher than an e-bike, because studies found eMTB riders working almost as hard as on a regular mountain bike.
There is no separate e-bike sport. An e-MTB rides the same trails as a mountain bike, so the routing stays the same; only the effort is estimated differently.