What magic parameters need to be added to the query? Can you tell me, where I can read about the parameters of requests for routing on public transport?
There’s a hard maximum allowed walking distance, defaulting to 1km. (A few lines down in the code you were looking at, but this one can be passed in the web request).
(This is one of the parameters that should go away. “Typical walking speed” (which is also a parameter) should be enough to approximate one’s willingness to walk.)