This bug is specifically detecting the new version of Edge (which uses "Edg/") and allows users with other strings "E/", "Ed/", and even Spartan based "Edge/".

This bug is specifically detecting the new version of Edge (which uses "Edg/") and allows users with other strings "E/", "Ed/", and even Spartan based "Edge/". Someone intentionally added code to single out Chromium based Edge.