In Windows 10, your user account information is part of the Privacy data which can be controlled with the Settings application. The user can revoke or grant access permissions for apps and users to this data. Recent Windows 10 builds can be configured to allow or deny apps access to their name, picture, and other account info for all your installed apps and the operating system itself. Only if allowed, the OS and installed apps will be able to use your user account information.
There still aren't enough extensions available for Microsoft Edge, which is mostly the company's fault — they took too long to introduce extension support at first and now they seem to be doing a very poor job on attracting developers to bring their products to the Windows Store. But this isn't stopping the company from making their own browser extensions — for third party browsers like Google Chrome.