Examine source code of keyn

{
  "manifest_version": 2,
  "name": "keyn",
  "developer": {
    "name": "James Elford",
    "url": "https://www.jameselford.com"
  },
  "version": "0.8.1",
  "description": "Navigate the world wide web with the power of your keyboard",
  "background": {
    "scripts": [
      "./lib/browser-polyfill.js",
      "./js/keyn.js"
    ]
  },
  "commands": {
    "pick-clickable": {
      "suggested_key": {
        "default": "Ctrl+Comma"
      },
      "description": "Click on a link or input"
    }
  },
  "permissions": [
    "activeTab"
  ],
  "applications": {
    "gecko": {
      "id": "{da833d6b-f202-4d54-b75d-dd2a2ce1264f}"
    }
  },
  "icons": {
    "16": "assets/keyboard_16.png",
    "48": "assets/keyboard_48.png",
    "128": "assets/keyboard_128.png"
  }
}