Where does “sælf” come from?

sælf (Old Danish) comes from Old Norse sjálfr, from Proto-Germanic selbaz, from Proto-Indo-European selbʰ-, from Proto-Indo-European s(w)e-, from Proto-Indo-European swé — self.

Ancestry of “sælf”, step by step

Step	Language	Word	Meaning
1	Old Norse	sjálfr	self
2	Proto-Germanic	selbaz	self
3	Proto-Indo-European	selbʰ-	one's own
4	Proto-Indo-European	s(w)e-	separate, apart; separate; apart; oneself; one's...
5	Proto-Indo-European	swé	self

Every word from Proto-Indo-European swé →Every word from Proto-Indo-European s(w)e- →Every word from Proto-Indo-European selbʰ- →