Examine source code of Text-to-Speech Reader

{
  "manifest_version": 2,
  "name": "Text-to-Speech Reader",
  "version": "1.0",
  "description": "Convert selected text into speech.",
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Text-to-Speech Reader"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{2bb6511f-ddc0-4100-99fb-46483db7e2b1}"
    }
  }
}