Synonym or breeding number (also FR 392-83) for the grape variety Souvignier Gris; see there.
The white grape variety is a new breed between Seyval Blanc x Zähringer. The true parentage was only determined by DNA analyses carried out in 2016; until then Cabernet Sauvignon x Bronner was accepted. It contains genes from Vitis lincecumii, Vitis rupestrisVitis...
Serious sources on the internet are rare - and Wine lexicon from wein.plus is one such source. When researching for my articles, I regularly consult the wein.plus encyclopaedia. There I get reliable and detailed information.
Thomas Götz
Weinberater, Weinblogger und Journalist; Schwendi