Examine source code of Gif Controls

{
  "manifest_version": 2,
  "name": "Gif Controls",
  "description": "Add playback controls to GIFs",
  "version": "1.0.0",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "64": "icon/64.png",
    "96": "icon/96.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "menus",
    "storage",
    "<all_urls>"
  ],
  "content_security_policy": "script-src 'self' 'wasm-unsafe-eval'",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "open_in_tab": false,
    "page": "options.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-scripts/player.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "content-scripts/player.css"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{69c2e11d-9cf2-44fa-85f2-a299dc027d77}"
    }
  }
}