HKUST Timetable Addon is a free Chrome extension developed by arcaneless. It falls under the category of Browsers, specifically Add-ons & Tools. This extension extends the availability of the Hong Kong University of Science and Technology official timetable planner.

With HKUST Timetable Addon, users can unblock restrictions on the planner before the validation period and also have the ability to look back at previous schedules. The main feature of this extension is to allow access to the planner for the upcoming semester. It removes the "validation period" limitation, enabling users to design their timetables in advance and view past semester schedules.

To use the extension, simply add it to your Chrome browser, go back to the planner, refresh the page, and you're all set. It's a convenient tool for HKUST students to plan their timetables more effectively.

Please note that HKUST Timetable Addon is an open-source project, and users are encouraged to contribute and create pull requests. If you encounter any technical issues, you can open an issue on the project's GitHub page.

It's important to mention that the developer, arcaneless, is not responsible for any data loss or errors that may occur on the HKUST official timetable planner website. This extension is solely created by an HKUST student for the convenience of other students.