When the production engine exists in physical form, we can absolutely discuss its capabilities. The XB-1 demonstrator is, using afterburner to get to speed, demonstrating other design features intended to keep the noise down.

The original plan was a commercial partner for the engines, but the big three - Rolls-Royce, Pratt & Whitney and General Electric - turned them down. It's one of the biggest remaining question marks in the entire project.

> The engine in XB-1 test plane is not the same that’s going in the production plane.

There IS no production plane, nor can there be. The last company they wanted to use for engines dropped them as a client years ago (others did earlier): https://english.alarabiya.net/business/aviation-and-transpor...