MVCE for emberjs/emberjs#15059

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

router.js

import Ember from 'ember';
import config from './config/environment';

const Router = Ember.Router.extend({
  location: 'none',
  rootURL: config.rootURL
});

Router.map(function() {
  this.route('files', function() {
    this.route('file', { path: '*path' });
  });
  this.route('rootfiles', function() {
    this.route('rootfile', { path: ':path' });
  });
});

export default Router;

routes.files.file.js

import Ember from 'ember';

export default Ember.Route.extend({
  model(params) {
    return {
      paramsPath: params.path,
      decodedPath: decodeURI(params.path)
    };
  }
});

routes.rootfiles.rootfile.js

import Ember from 'ember';

export default Ember.Route.extend({
  model(params) {
    return {
      paramsPath: params.path,
      decodedPath: decodeURI(params.path)
    };
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
{{link-to 'non-glob example' 'rootfiles.rootfile' '/files/my file with spaces.json'}}
{{link-to 'glob example' 'files.file' '/files/my file with spaces.json'}}
<br>
<br>
{{outlet}}
<br>
<br>

templates.files.file.hbs

<p>params.path: {{model.paramsPath}}</p>
<p>decodeURI(params.path): {{model.decodedPath}}</p>

templates.rootfiles.rootfile.hbs

<p>params.path: {{model.paramsPath}}</p>
<p>decodeURI(params.path): {{model.decodedPath}}</p>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}