I am customizing the opentripplanner webapp according to my needs. it has 5 different base layers. but in code (in map.js and OpenLayersUtils) i can't find where it adds these layers to map.
There you see:
In there is a line:
That looks like a variable thing, a bit below that you see that this otp config object if exists is being used to set up layers
Looking at the rest of the code, it looks like you have 3 basic layers: WMS + the carto + ortho layer. The other 2 come from something dynamically configured it seems. That would be my first guess. The WMS layer is defined in makeMap, in this file