Examine source code of librevent

{
  "manifest_version": 2,
  "name": "librevent",
  "short_name": "librevent",
  "description": "A tool for manage, access, fetch and organize events stored on fediverse protocol",
  "version": "0.3.3",
  "author": "Data Liberation Network",
  "icons": {
    "16": "librevent-16.png",
    "48": "librevent-48.png",
    "128": "librevent-128.png"
  },
  "browser_action": {
    "default_icon": "librevent-16.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "storage",
    "https://*.facebook.com/",
    "https://libr.events/"
  ],
  "background": {
    "scripts": [
      "./background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.facebook.com/*"
      ],
      "js": [
        "./app.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "*.png"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f518e305-e3ff-4acd-90b0-af929fcd7e83}"
    }
  }
}