In December 2024, Hober contributed to the w3ctag/design-principles repository by introducing a new API design guideline focused on side-effectful functions. The work established that such functions should return undefined, aligning with Command-Query Separation to promote safer API evolution and clearer semantics for consumers. Hober implemented this principle with an illustrative example using HTML and JavaScript, specifically referencing HTMLMediaElement.play() to demonstrate the benefits. The contribution emphasized maintainability and future-proofing of web APIs, drawing on skills in API design, web standards, and documentation. Over the month, Hober delivered one feature, reflecting thoughtful, standards-driven engineering with a focus on long-term clarity.