Microsoft XML Namespace URL Down

[mikedh]

It looks like the URL's used as namespaces are down. Quoting the specification:

C.3 Namespaces
3D Model http://schemas.microsoft.com/3dmanufacturing/core/2015/02
Triangle Sets http://schemas.microsoft.com/3dmanufacturing/trianglesets/2021/07
Mirroring http://schemas.microsoft.com/3dmanufacturing/mirroring/2021/07

All of these URLs show the same error page:

The resource you are looking for has been removed, had its name changed, or is temporarily unavailable.