Switch Search Engine does not collect, store, transmit, or share any personal data.
What the extension does

Reads the search query from the current search results page to redirect it to another engine
Saves your preferences (enabled engines, their order, UI settings) locally in your browser using the browser's built-in storage API

What data is stored
Your preferences are stored exclusively in your browser's local/sync storage. This data never leaves your device unless you use your browser's built-in sync feature, in which case it is handled entirely by your browser vendor (Mozilla).
What data is not collected

No personal information
No browsing history
No search queries
No usage statistics or analytics
No data is sent to any server

Permissions

tabs: Used to read the current tab's URL and redirect it to the selected search engine.
storage: Used to save your settings locally in the browser.
Host permissions: Used to inject the engine switcher bar on search result pages and read the current search query from the page.

Third parties
No data is shared with any third party. The extension does not use any external services, analytics tools, or remote code.