frow what was Lexx bred?

Ive always gone with what the plot says.

Lexx plans were based from the Astral B, stored in Stans tooth. Probably the Heretics couldent build it.

However Brizon could, and did. Thus the Lexx was born.

How did the Heretics get that knowledge? Id have to guess that shortly before the Brunnin G were destroyed we learn they contacted the outside world(Brigadoom). But about what? This could be part of it, maybe they downloaded their knowledge to the heretics.