Examine source code of Facebook Post Screenshot

{
  "description": "Web Extension to save Facebook posts as images",
  "manifest_version": 2,
  "name": "Facebook Post Screenshot",
  "version": "1.11.4",
  "homepage_url": "https://github.com/hckr/fb-post-screenshot",
  "icons": {
    "72": "icons/icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.facebook.com/*"
      ],
      "js": [
        "content/content.js",
        "content/watch_group.js"
      ],
      "css": [
        "content/content.css"
      ]
    },
    {
      "matches": [
        "*://hckr.pl/fb-post-screenshot/*"
      ],
      "js": [
        "content/content_homepage.js"
      ],
      "css": [
        "content/content_homepage.css"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background/storage_defaults.js",
      "background/register_on_up_off_boarding.js",
      "background/background.js"
    ]
  },
  "options_ui": {
    "page": "options/options.html"
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "72": "icons/icon.png"
    },
    "theme_icons": [
      {
        "light": "icons/icon-light.png",
        "dark": "icons/icon.png",
        "size": 72
      }
    ],
    "default_title": "Facebook Post Screenshot",
    "default_popup": "popup/popup.html"
  },
  "permissions": [
    "<all_urls>",
    "downloads",
    "storage"
  ],
  "applications": {
    "gecko": {
      "id": "{ba702296-2817-46a3-a08d-d7aaf194b9ba}",
      "strict_min_version": "54.0"
    }
  }
}