Windows Insider Channels are rolling out to Windows 10 customers enrolled in the program as announced earlier this month. Windows Insiders’ devices will be automatically moved to channels based on the currently selected ring and on the quality of the experienced they are expecting, without any user interaction. The Fast and Skip Ahead rings will become the Dev Channel, the Slow ring will shift to the Beta Channel, and the Release Preview ring will be converted into the Release preview Channel. Windows Insider channels are aligned with the new names Microsoft announced last month for existing channels for Microsoft 365 Apps.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-officially-launches-windows-10-insider-channels/