Introduction to the BioChemical Library (BCL): An application-based open-source toolkit for integrated cheminformatics and machine learning in computer-aided drug discovery. Front. Pharmacol., (13):833099, Frontiers Media SA, February 2022. [PUMA: BCL; QSAR; biochemical cheminformatics; deep design; discovery; drug library; network; neural open-source topic_lifescience]