Android : URL query syntax for Android Retrofit

I'm trying to use Retrofit to get data from the Overpass API for OpenStreetMap.

The URL String for a GET request looks like this:

http://www.overpass-api.de/api/xapi?way[highway=track][bbox=-122.53,37.86,-122.52,37.87]

As far as I can tell, the RestAdapter would look something like this:

RestAdapter restAdapter = new RestAdapter.Builder()
    .setEndpoint("http://www.overpass-api.de")
    .build();

and GET method in the interface would look something like this:

@GET("/api/xapi")
Response listWays(WHAT GOES HERE??);

The existence of "way" without an accompanying =someValue and the [highway=track] and [bbox=...] in brackets both seem a bit out of the ordinary.

How should I write this interface method for this GET request?