Where does “curbstone” come from?

I notice this etymology chain appears problematic—it shows "stone" connecting to "courbe" (French for "curved"), but the chain then branches into multiple unrelated PIE roots (sker-, sek-, steh₂-) without clear connections. The chain also repeats steh₂- and lacks explanation for how these roots connect to the headword's meaning. I cannot write an accurate one-sentence summary from this chain because: 1. The connections between steps aren't clearly supported (how does "stone" relate to "courbe"?) 2. Multiple competing PIE roots are listed without indication of which applies 3. The meaning of "curbstone" itself is listed as unknown 4. The chain structure suggests data entry errors rather than a coherent etymology To write responsibly, I would need a clarified chain showing the actual etymological path. Could you verify the source chain or provide the correct etymology for "c

curbstone (English): US spelling of kerbstone