Why does my Sails.js app have a route I never added

I have created a new Sails app, and so far I have created an api using sails generate api guitar, and then added this code in the controller:

module.exports = {    
    fender: function(req, res){  
        console.log(req.params);
        res.notFound();  
    }
};

As expected, when I go to http://localhost:1337/guitar/fender I get a 404 error (that's the response I programed). But what I don't get is, if I go to http://localhost:1337/guitar/fender/4, the console will show [ id: '4' ]. I seems that somewhere there's a GET /guitar/fender/:id (using Express/Rails syntax here) sort of URL. But I don't see it anywhere, not in config/routes.js or anywhere else.

So, does Sails.js create a :id for every controller action automatically? Or am I missing something here?

I tried some things, such as adding this to the config/routes.js file:

'get /guitar/fender/:brand': 'GuitarController.fender'

And then when I go to the URL again, [ brand: '4' ] will be printed instead of id.

So my final question is: Does Sails.js automatically make an :id for every controller action?

(I couldn't find this on the docs either)

via Felo Vilches