Right, one that by my understanding “pools” searches, in a way. As their blog put it in 2023:
“Mullvad Leta uses the Google Search API as a proxy, caching each search. These cached results are shared amongst all users, reducing costs and improving privacy. This service is user-supported and doesn't rely on ads or data selling.”
That short period of time is likely to pool a group of users. Even if not, using Mullvad as a personal proxy for Google is a better privacy-conscious decision than using Google directly.
I presume that's because calling it privacy-focused is considered editorializing. I'd at least hope it can have "(search engine)" or similar because I had no idea what it was before clicking.
I quoted their FAQ; it's not editorializing: https://leta.mullvad.net/faq