You can have a first look below:
At the bottom of the API Browser, there are some mainly used APIs already listed under Quick Filters. You can click any of them to quickly navigate to API’s documentation.
Once you select any APIs name from the drop-down, then you will see another drop-down with further selection for API version.
Once you select any API (click on the API name under name” column), you will be shown the documentation of that API with its definition, classes, structs and interfaces.
You can change the namespace and API version from the same page, using the drop-downs on the left top side.
There are two theme selections available:
In the months to come, Microsoft is going to add more SDKs to this experience. I am missing Office 365 and Microsoft Graph APIs reference here and I hope, it will be added by Microsoft in near future.
Note: This article was published by me at C# Corner here.