Examine source code of Send Selection to Gmail

{
  "manifest_version": 2,
  "name": "Send Selection to Gmail",
  "version": "1.2.2",
  "description": "Right-click selected text to open a Gmail compose window. Includes an Options page to set destination email, default subject, and behavior.",
  "permissions": [
    "menus",
    "tabs",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": true
  },
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "send-selection-to-gmail@juliano.local",
      "strict_min_version": "91.0",
      "data_collection_permissions": {
        "required": [
          "personallyIdentifyingInfo"
        ]
      }
    }
  }
}