Is Content Site Search Guru safe?

Searches specific content sites from the browser address bar using @ commands.

This extension lets you type @, a website domain, and a search query in the address bar to open results for that site. It changes the default search engine to search.searchsafe.tech, powered by Yahoo, as a placeholder for address-bar autocomplete, and it says you can switch providers between Yahoo, Google, and Bing in settings. Optional cookie access is described as supporting search engine customization and autocomplete default suggestions.