We introduce a large-scale dataset of the complete texts of free/open source software (FOSS) license variants. To assemble it we have collected from the Software Heritage archive—the largest publicly available archive of FOSS source code with accompanying development history—all versions of files whose names are commonly used to convey licensing terms to software users and developers. The dataset consists of 6.5 million unique license files that can be used to conduct empirical studies on open source licensing, training of automated license classifiers, natural language processing (NLP) analyses of legal texts, as well as historical and phylogenetic studies on FOSS licensing. Additional metadata about shipped license files are also provided, making the dataset ready to use in various contexts; they include: file length measures, detected MIME type, detected SPDX license (using ScanCode), example origin (e.g., GitHub repository), oldest public commit in which the license appeared. The dataset is released as open data as an archive file containing all deduplicated license blobs, plus several portable CSV files for metadata, referencing blobs via cryptographic checksums.

Stefano Zacchiroli is full professor of computer science at Télécom Paris, Polytechnic Institute of Paris. His current research interests span digital commons, open source software engineering, computer security, and the software supply chain. He is co-founder and CTO of Software Heritage, the largest public archive of software source code. He is a Debian developer since 2001, where he served as Debian project leader from 2010 to 2013. He is a former board director of the Open Source Initiative (OSI) and recipient of the 2015 O’Reilly Open Source Award.