Illumination properties of glazing samples and radiance input file

Dear all,
I'm currently working with a glazing manufacturer who is providing me with
glazing properties in .is and .brdf files.
I've used xml files previously in Radiance to work with BSDF primitives
and I wondered if some of you have ever come across these extensions and
knew if they can be converted into a readable format by Radiance.
Thanks in advance,

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