Custom locations are a supported public API

[ef4]

See docs at:

https://github.com/emberjs/ember.js/blob/60d2e0cddb353aea0d6e36a72fda971010d92355/packages/%40ember/routing/location.ts#L31-L33

If you create app/locations/whatever.js you can set Router.location to "whatever" to resolve it.

In addition to using the resolver in this way with a custom string, you can avoid stringly resolution by passing a Location instance directly.