https://www.bleepingcomputer.com/news/microsoft/unknown-dev-brings-libreoffice-to-windows-10-via-the-microsoft-store/

The free and open-source Microsoft Office challenger called LibreOffice is now available in the Microsoft Store for Windows 10 PCs and Tablets. What is concerning, though, is that the app's publisher does not appear to be LibreOffice's actual developer, but rather a 3rd party that also prompts you to purchase it for $2.99.

LibreOffice is a free and open source office suite developed by The Document Foundation. The LibreOffice app on the Microsoft Store, though, was quietly published by a developer account named ".net" on July 7th and allows you to install it for free or purchase it for $2.99.