Save-Data: on is a free browser extension developed by Aleksandersen for the Chrome platform. It falls under the category of Browsers and specifically the subcategory of Add-ons & Tools. This extension automatically enables data-savings mode at compatible websites.

With Save-Data: on, you can inform websites that you prefer to save data and costs. When visiting compatible websites, webpages will adjust to reduce data downloads, resulting in lower quality images and fewer media elements.

Unlike other data compression proxies like the Data Saver/Lite option in Google Chrome or Opera Turbo and Yandex.browser Turbo mode, Save-Data: on works by sending the "Save-Data: on" HTTP header with every request. This ensures that the extension is not only efficient but also transparent in its data-saving process.

If you're looking to reduce your data usage and save costs while browsing, Save-Data: on is a handy extension to have in your Chrome browser.