OR Microsoft updated the design of the website for the Program Windows Insider. The new design clearly explains the purpose of the program and describes the new channels in which any interested user can participate.
The Fast Ring is done Dev Channel, the Slow ring became the Beta Channel and the Release Preview ring became the Release Preview Channel. The new name scheme is reminiscent of the name used by Microsoft for the development of the Edge browser.
The new shape in the settings of Windows 10 describes the changes made to the Insider program, but the new site also fully reflects the changes.
It also states as you can see in the image above which build exists on which channel.
The company considers that this new design is more user-friendly and understandable.