The UI aesthetics look similar to the excellent Rill, also powered by DuckDB: https://www.rilldata.com/
Rill has better built in visualizations and pivot tables and overall a polished product with open-source code in Go/Svelte. But the DuckDB UI has very nice Jupyter notebook-style "cells" for editing SQL queries.
http://bookmarked.in -- It's private, does one thing and does it really well - saves a link to a list of other links! Sometimes I just want to save a link and continue browsing without being hassled for extraneous details like tags or descriptions. Features=1 -> save a URL.