When users of the Chromium-based Microsoft Edge use Google Docs, the service is stating that the browser is not supported. As the new Microsoft Edge uses the same HTML engine as Chrome and is clearly supported, some users feel that Google is playing unfairly. A browser useragent is a unique string associated with a browser and used to identify it. When the browser connects to a website, the browser’s useragent string is also sent to the web site so that the site can offer customizations based on the browser.
Source: https://www.bleepingcomputer.com/news/microsoft/google-docs-says-chromium-based-microsoft-edge-is-not-supported/