BFSI institutions continue to depend on legacy platforms like COBOL, PL/SQL, and early Java, where poor documentation makes systems difficult to manage and modernize. Critical business rules, including financial calculations and compliance logic, remain buried in code, creating operational risks. Code reverse engineering helps uncover hidden logic, dependencies, and workflows within these systems. Modern tools automate code-to-documentation by analyzing source code and generating structured outputs. This enables clear functional understanding, improves compliance visibility, supports governance, accelerates modernization initiatives, and reduces reliance on individual legacy experts.