This open access book constitutes the refereed proceedings of the 15th IFIP WG 2.13 International Conference on Open Source Systems, OSS 2019, held in Montreal, Quebec, Canada, in May 2019. The 10 revised full papers and 5 short papers presented were carefully reviewed and selected from 35 submissions. The papers cover a wide range of topics in the field of free/libre open source software (FLOSS) and are organized in the following thematic sections: mining OSS data; organizational aspects of FLOSS projects; FLOSS adoption; FLOSS cost and licenses; and FLOSS education and training.

This book constitutes revised selected papers from the 10th Brazilian Workshop on Agile Methods, WBMA 2019, held in Belo Horizonte, Brazil, in September 2019. The 6 full and 4 short papers presented in this volume were carefully reviewed and selected from 21 submissions.Accepted papers focus on agile methods; experimental studies with agile; software engineering education with agile; agile project management.