Code Navigation and Understanding Existing Codebases Questions

Ability to read and understand unfamiliar or partially implemented repositories, identify where functionality lives, trace execution paths, and safely extend code. Candidates should demonstrate tactics for onboarding into a codebase such as locating entry points and core modules, reading tests and documentation, using debugger and logging to observe runtime behavior, understanding build and dependency systems, and making incremental, test backed changes. Interview prompts often present snippets or partial implementations and ask candidates to explain behavior, find bugs, or design small extensions consistent with the existing architecture.