Since our software is privacy-first website analytics, there's typically less to do on your end because we collect such a minimal amount of data from visitors. That's why we believe you don't need annoying cookie notices with Fathom because we comply with privacy laws around the world (you can read more about our legal compliance with privacy laws).
To add mention of the data you collect from your website analytics (in this case, Fathom Analytics), you can use the following text.
The purpose of us using this software is to understand our website traffic in the most privacy-friendly way possible so that we can continually improve our website and business. The lawful basis as per the GDPR is "Article 6(1)(f); where our legitimate interests are to improve our website and business continually." As per the explanation, no personal data is stored over time.
While adding this text can assure your website visitors that you value their privacy, there is no legal requirement to add this (or similar).