Looks like they're moving to Chromium.
https://www.theregister.co.uk/2018/12/04/chromium_edge_microsoft/
https://www.theverge.com/2018/12/4/18125238/microsoft-chrome-browser-windows-10-edge-chromium
https://www.theregister.co.uk/2018/12/04/chromium_edge_microsoft/
https://www.theverge.com/2018/12/4/18125238/microsoft-chrome-browser-windows-10-edge-chromium