Better Roblox Friendslist does not collect any data of any kind.

Better Roblox Friendslist has no home server.
Better Roblox Friendslist doesn't embed any kind of analytic or telemetry hooks in its code.

The only remote server that RoSearcher contacts is owned by the Roblox Corporation and their privacy policy can be found: https://en.help.roblox.com/hc/en-us/articles/115004630823-Roblox-Privacy-and-Cookie-Policy-