At the moment it is possible for service type wms,wmts,tile to manipulate the capabiities url like this

https://host/service/wms/foo/bar?request=GetCapabilities&Service=WMS&Version=1.3.0

real url is i.e. https://host/service/wms?request=GetCapabilities&Service=WMS&Version=1.3.0

In the capabilities then all onlineresource params show the additional /foo/bar too.

For wmts and tms i can fix that with little changes in request/wmts.py and request/tile.py

see https://github.com/hschiebold/mapproxy/tree/no_foo_in-cap_url/

Unfortunatly i have still no idea how to fix that for type wms and i'm not realy shure if my fixes are correct in general all cases, and not only my ones.

Could anybody give me a hint to comlete that issue - i will provide a pr than.

Thanks in advance

Holger