Worked on the mdn/browser-compat-data repository to enhance the accuracy and consistency of Opera browser compatibility information. Focused on correcting data for CSS properties such as box-decoration-break and speak, as well as the HTML fieldset.disabled attribute and the HTTP header Cross-Origin-Opener-Policy. Addressed Opera’s support for the hidden="until-found" attribute and standardized internal property naming by renaming until-found_value to until-found. All changes were implemented using JSON and applied browser compatibility data management skills to ensure data reliability. Delivered targeted, traceable commits that improved data quality, reduced confusion for developers, and maintained alignment with established naming conventions across the dataset.