This brings still another thought to my mind. Aren't there someThat's "trunk" as in "tree trunk", the core or principal part to which secondary pieces ("branches") are attached.
In German "stammen" has a connotation of parentage or origins ("woraus stammen Sie?")
that is far weaker for "trunk" in English.
"Trunk" in English connotes "importance" much more than it does "historical origin",
whereas in German (and I am far from highly fluent in German) the two senses
of the word are more equal.
All terms in the direction of main, principal, primary etc. contain, inI'd got for something like "historical core network" or "original network".