SYN: Ultra-Scale Software Evolution Comprehension.

The comprehension of very large-scale software system evolution remains a challenging problem due to the sheer amount of time-based (i.e., a sequence of changes) data and its intrinsically complex nature (i.e., heterogeneous changes across the entire system source code). It is a necessary step for program comprehension, as systems are not simply created out of thin air in a bang, but are the sum of many changes over long periods of time, by various actors and due to various circumstances. We present SYN, a web-based tool that uses versatile visualization and data processing techniques to create scalable depictions of ultra-scale software system evolution. SYN has been successfully applied on several systems versioned on GitHub, including the nearly 20-year history of the Linux operating system, which totals more than one million commits on more than 100k evolving files. Webpage of the tool and demo video: https://syn.si.usi.ch