Rill founder here, I have no comment on the UI similarity :) but I would emphasize our vision is building DuckDB-powered metrics layers and exploratory dashboards -- which we presented at DuckCon #6 last month, PDF below [1] -- and less on notebook style UIs like Hex and Jupyter.
Rill is fully open-source under the Apache license. [2]
ydata-profiling does open-source Exploratory Data Analysis (EDA) with Pandas and Spark DataFrames and integrates with various apps: https://github.com/ydataai/ydata-profiling #integrations, #use-cases
Alongside several great talks including Rusty Conover presenting Airport - Arrow + DuckDB — and Christophe Blefari (Bl3f) introducing a new, lightweight orchestrator called yato.
Rill is fully open-source under the Apache license. [2]
[1] https://blobs.duckdb.org/events/duckcon6/mike-driscoll-rill-...
[2] https://github.com/rilldata/rill