Examine source code of Saka Key

{
  "name": "Saka Key",
  "version": "1.26.3",
  "author": "Brandon Kalinowski, Sufyan Dawoodjee, Neil Macintyre",
  "description": "A keyboard interface to the web",
  "manifest_version": 2,
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "background": {
    "scripts": [
      "background_page.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "48": "logo.png"
    },
    "default_popup": "options.html"
  },
  "options_ui": {
    "page": "options.html",
    "chrome_style": false,
    "open_in_tab": true
  },
  "icons": {
    "16": "logo.png",
    "48": "logo.png",
    "128": "logo.png"
  },
  "permissions": [
    "tabs",
    "activeTab",
    "sessions",
    "storage",
    "unlimitedStorage",
    "<all_urls>",
    "clipboardRead",
    "downloads",
    "cookies"
  ],
  "web_accessible_resources": [
    "content_script.js",
    "content_script.js.map",
    "background_page.js.map",
    "content_script_loader.js.map",
    "options.js.map",
    "info.js.map",
    "Roboto-Regular.ttf",
    "config_basic.json",
    "config_command.json",
    "config_developer.json",
    "config_hints.json",
    "default_basic.json",
    "default_command.json",
    "default_developer.json",
    "default_hints.json"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_script.js"
      ],
      "all_frames": true,
      "run_at": "document_idle",
      "match_about_blank": true
    }
  ],
  "applications": {
    "gecko": {
      "id": "{46104586-98c3-407e-a349-290c9ff3594d}"
    }
  }
}