Based on data I've gathered through quantitative and qualitative surveying, 

I can detect no application of Provider Backbone Bridging (MAC-in-MAC). 

Please bear with me while I clarify that I am not enquiring about Provider Bridging (QinQ).

I would like to ask specifically about knowledge of deployments of PBB. 

If anyone would care to share data points, on- or off-list, I would love to know about them. 

I am open to anything on the subject of PBB's adoption that you are free to share with me. 

I am bound by GDPR and will anonymize any data that is not open for public disclosure.

Thank you!

Etienne