Duolingo Memo is a free Chrome extension developed by Matías Duhalde. It falls under the category of Browsers and specifically the subcategory of Add-ons & Tools. The main purpose of this extension is to remember and auto-fill your answers on Duolingo, the popular language-learning platform.

Originally created to address the tediousness of Legendary Challenges on Duolingo, where the exercise pool is limited and only two mistakes are allowed, Duolingo Memo aims to make retrying these challenges less frustrating. With this extension, you no longer have to retype the same answers repeatedly as it remembers your correct answers and automatically fills them in.

While the extension was initially designed for exercises of the "Translate" type, where you have to type the translation of a given sentence, it has been expanded to support other exercise types as well. The developer also plans to continue expanding the functionality of the extension in the future.

Duolingo Memo is a useful tool for Duolingo users who want to save time and avoid repetitive typing while completing challenges. With its ability to remember and auto-fill answers, it enhances the user experience and makes language learning on Duolingo more efficient.