Once is a productivity extension available for the Chrome platform. Developed by davidchuyaya, this free add-on falls under the category of Browsers and specifically the subcategory of Add-ons & Tools.

Once is designed to help users stay focused by limiting their visits to selected websites on a daily basis. With this extension, users can set a limit of one visit per day to specific sites, preventing them from constantly switching between distracting pages. By enabling Once in incognito mode, users can even prevent themselves from browsing certain websites altogether.

However, it's important to note that Once may not be suitable for those who tend to leave sites open without closing them. This extension is most effective for users who actively manage their browsing habits and want to increase their productivity.

For more information and details about Once, you can visit the developer's GitHub page provided below.