Examine source code of RGAA Checker

{
  "manifest_version": 2,
  "name": "RGAA Checker",
  "description": "A browser extension to check compliance with the RGAA standard",
  "version": "0.28.0",
  "icons": {
    "48": "images/icon48.png",
    "96": "images/icon96.png"
  },
  "browser_action": {
    "default_popup": "rgaa-checker-popup.html",
    "default_icon": {
      "48": "images/icon48.png",
      "96": "images/icon96.png"
    }
  },
  "permissions": [
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "devtools_page": "rgaa-checker-devtools.html",
  "web_accessible_resources": [
    "rgaa-checker-panel.html",
    "app.js",
    "app.css"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{e6daa734-d58e-42a7-8be1-a7027eccd33f}"
    }
  }
}