FeatOutline: Feature-Oriented Repository Summarization for Enhanced Code Comprehension and Maintenance

Repository-level code summaries are typically organized around directories and files, making functionality that spans multiple artifacts difficult to see and trace to its implementation. We present FeatOutline, a feature-oriented repository summarization approach that organizes a repository around its functionality and connects each generated feature directly to the methods that implement it. FeatOutline combines structural dependencies and semantic similarity to form functionally cohesive groups at the file and method levels, synthesizes these groups into features, and organizes related features into epics. Comparative experiments on eight open-source Java repositories demonstrate that FeatOutline captures documented functionality more completely and traces generated features to source code more accurately. A controlled maintenance study with 16 participants further shows that FeatOutline increases task success by 28.1 percentage points and reduces completion time by approximately one-third relative to a state-of-the-art repository summarization approach. These findings demonstrate that organizing repository code around method-grounded features provides developers with a more effective way to understand, navigate, and maintain unfamiliar repositories.