Anyone understand the significance of the S and D marking on the nipple of a 4700/5800 derailleur inner cable?

The dealer manual shows different markings for the 9000 and 6800 series as well

I’ve just swapped the S and D marked Shimano cable for a Clarke’s replacement it works the same. I thought it might be the Italian left and right, but it doesn’t seem to be

Thanks

Could be for production line use, maybe short on front, long on rear? Just looked at DM’s on techdocs for inner cable 1 & 2, and of all the inners they list,only one is marked “S”, and that’s a 1.1mm , none of the others show markings at all, and they’re all 1.2mm. We always use YPK stainless 1.1mm slick inners on everything without any issues, doubt it’s anything worth worrying over.

Thanks for looking. The S and D are on the same nipple, one letter each side. The STI dealer manual shows the lettering in illustrations but doesn’t refer to it in words

No obvious angle on the nipple. It’s a 1.2mm cable in the DM, and 4700/5800 only…

“…doubt it’s anything worth worrying over.” Absolutely, thanks again

It’s so you can fit them the right way round – sinister and dexter.