Where does “Ѕвонко” come from?

Ѕвонко (Macedonian) comes from Macedonian -ко, from Proto-Slavic -ьko.

Ancestry of “Ѕвонко”, step by step

Step	Language	Word	Meaning
1	Macedonian	-ко	Suffix appended to words to create a masculine...
2	Proto-Slavic	-ьko	—