Examine source code of Webcompat.com Reporter

{
  "manifest_version": 2,
  "name": "webcompat.com reporter",
  "description": "Report website compatibility issues at webcompat.com",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://webcompat.com/"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "tabs",
    "activeTab",
    "contextMenus",
    "https://webcompat.com/",
    "<all_urls>"
  ],
  "icons": {
    "32": "icon32.png",
    "48": "icon48.png",
    "64": "icon64.png",
    "128": "icon128.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "icon32.png",
      "32": "icon32.png",
      "48": "icon48.png",
      "64": "icon64.png",
      "128": "icon128.png"
    },
    "default_title": "Report Site Issue"
  },
  "default_locale": "en",
  "version": "0.6.0",
  "applications": {
    "gecko": {
      "id": "jid1-mjpB54bRzP9Zxw@jetpack",
      "strict_min_version": "49.0a1"
    }
  }
}