It's not white labelled Plausible. The creators of it are on Twitter if you are interested in following their journey (i.e. twitter/TheBuilderJR). It's built on Tinybird, Supabase, and Next.js, while Plausible is built in Elixir using plain Postgres and Clickhouse, and Phoenix.
A lot of relatively new analytics services tend to have similar looking frontends these days I've noticed though.