Where does “Träubchen” come from?

Träubchen (German) comes from German traube, from Middle High German trūbe, from Old High German drūbo, from Proto-West Germanic þrūbō, from Proto-West Germanic þrubō, from Proto-Germanic þrubô, from Proto-Indo-European trup-ḗn ~ trup-nés, from Proto-Indo-European -ḗn — Derives nouns from roots.

Ancestry of “Träubchen”, step by step

StepLanguageWordMeaning
1Germantraubegrape
2Middle High Germantrūbegrape fruit
3Old High Germandrūbogrape
4Proto-West Germanicþrūbōcluster; grape
5Proto-West Germanicþrubōcluster, bunch
6Proto-Germanicþrubô
7Proto-Indo-Europeantrup-ḗn ~ trup-nés
8Proto-Indo-European-ḗnDerives nouns from roots
Every word from Proto-Indo-European -ḗn