PVS-Studio analyzes source code and finds various errors and code quality issues across multiple languages and frameworks. The document highlights 20 examples of issues found, including uninitialized variables, unreachable code, incorrect operations, security flaws, and typos. PVS-Studio is able to find these issues using techniques such as data-flow analysis, method annotation analysis, symbolic execution, type inference, and pattern-based analysis to precisely evaluate the code and pinpoint potential bugs or code smells.