q parameter appears in rendertron listening

[AlsonicTech]

While listening to rendertron, all the urls are sent with a "q" parameter, like in this example.

Listening on port 3000
<-- GET /render/https://mydomain.com/foo/bar/?q=%foo%bar
--> GET /render/https://mydomain.com/foo/bar/?q=%foo%bar 200 1,975ms 17.83kb

Also If I do a "curl -L https://mydomain.com/foo/bar" I still get the same as above.
Tried it with and without caching, and it's the same.
Why is this happening?