Examine source code of Simple Dimmer

{
  "manifest_version": 2,
  "name": "simple-dimmer",
  "description": "a simple way to dim webpages, including video",
  "version": "1.0.0",
  "icons": {
    "32": "/icon.svg",
    "48": "/icon.svg",
    "64": "/icon.svg",
    "96": "/icon.svg"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "/content_script.js"
      ]
    }
  ],
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "48": "/icon.svg"
    },
    "default_title": "simple-dimmer",
    "default_popup": "/popup.html"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d8adde50-7f33-43c4-93dd-322f44b5fca7}"
    }
  }
}