Would it be possible to include the departure airport in the navlog section? At the moment, it starts with the first point along the SID/route and ends at the destination airport.
Probably not, this would break many existing integrations.
Each navlog fix contains details for the preceding leg (the distance, time, fuel, etc are all from the previous waypoint). The origin airport does not have a previous waypoint, so there is little point in including it.
Depending on what you’re trying to do, it should be possible to create the first line (for the origin airport) based on other data in the XML.