No.
Since first mention of cbeta no member has stepped forward.
This would be a good place to do so.
NDA is not or has not been Jolla style.

[speculation: on, fanboy: off]
My take is cbeta is limited to jolla employees as of yet.
Makes sense for them.
Reliable feedback, no public horrasment.
Hopefully they have good results and expand cbeta fast.
[speculation: off, fanboy: auto]