Where does “świętojańskie” come from?

świętojańskie (Polish) comes from Polish świętojański, from Polish Jan, from Late Latin Iohannes, from Koine Greek Ἰωάννης, from Hebrew יוחנן, from Hebrew חנון, from Moroccan Arabic خنونة, from Arabic خُنَّة.

świętojańskie (Polish): cash deposit given to servants, farmhands, etc., usually given on Michaelmas, i.e., a quarter before the New Year