Interesting, how does the path canonicalize if you do that?

A traditional UNC path becomes "\??\Device\MUP\ComputerName\ShareName" as an NT Object Namespace path (Or "\\?\GLOBALROOT\Device\MUP\ComputerName\ShareName" as a file path)

If you change the port number or protocol, is that encoded somewhere in the native path?

Fun thing to do, you can use "7-Zip File Manager" to explore unusual styles of file paths. A path like "\\?\GLOBALROOT\Device\MUP\ComputerName\ShareName\" will work fine in 7-zip file manager, even though Windows Explorer (and File Dialogs) will reject such a path.