Examine source code of Background Replace

{
  "manifest_version": 3,
  "name": "Background Replace",
  "version": "1.0.0",
  "description": "Right-click an image to replace its background with a selected theme.",
  "browser_specific_settings": {
    "gecko": {
      "id": "background-replace@addon",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": [],
        "collected": [],
        "purposes": []
      }
    }
  },
  "permissions": [
    "contextMenus"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ]
}