This is a relative pronoun that relativizes inanimates. In the fourth sentence of the Babel text
Ä“ teteÃ± ien hÄ“ja Ã±anna jamÄonre nÄ«kan jakÅnÅr ja Ã±i jÅl rÄ anÄ«stÄ«li;
ja relativizes jakÅnÅr. Ã±i jÅl rÄ anÄ«stÄ«li is “make the top of it to heaven” and it is jakÅnÅr “a tower”.
And they to each other said: We should make a city with a tower whose top is to heaven.