Examine source code of Automatic Snapshots

{
  "author": "igorlogius",
  "homepage_url": "https://github.com/igorlogius/automatic-snapshots",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_area": "navbar",
    "theme_icons": [
      {
        "light": "dark.png",
        "dark": "icon.png",
        "size": 128
      }
    ]
  },
  "commands": {
    "_execute_browser_action": {}
  },
  "icons": {
    "128": "icon.png"
  },
  "manifest_version": 2,
  "name": "Automatic Snapshots",
  "description": "Automatically save snapshots of the current active tabs visible area with a custom delay",
  "permissions": [
    "storage",
    "tabs",
    "<all_urls>"
  ],
  "options_ui": {
    "page": "options.html"
  },
  "version": "1.0.1",
  "browser_specific_settings": {
    "gecko": {
      "id": "{31aaea05-566d-43cf-b848-499498df027c}"
    }
  }
}