Examine source code of OmniGIF

{
  "manifest_version": 2,
  "name": "OmniGIF",
  "description": "Grab any webpage image to convert, edit, compress, or make GIFs — right-click or pick on the page.",
  "version": "0.1.1",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "contextMenus",
    "activeTab",
    "scripting",
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "extension@omnigif.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "websiteContent"
        ]
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "OmniGIF",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_idle",
      "js": [
        "content-scripts/content.js"
      ]
    }
  ]
}