Examine source code of Background

{
  "manifest_version": 3,
  "name": "Background",
  "description": "Sets a custom background image for all websites",
  "version": "0.0.5",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "96": "icon/96.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "scripting"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "author": "rxliuli",
  "action": {
    "default_icon": {
      "16": "icon/16.png",
      "32": "icon/32.png",
      "48": "icon/48.png",
      "96": "icon/96.png",
      "128": "icon/128.png"
    },
    "default_popup": "popup.html",
    "default_title": "Background"
  },
  "homepage_url": "https://rxliuli.com/project/background",
  "browser_specific_settings": {
    "gecko": {
      "id": "background@rxliuli.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options.html"
  }
}