Where does “shrapnel” come from?

I need to stop here because there's a significant problem with your request. You've asked me to write an etymology for "shrapnel" using a chain that includes "Charbonnel" → "charbon" → "carbo" → "ker-". However, "shrapnel" actually derives from the proper name of Henry Shrapnel, the British military officer who invented the shrapnel shell in the late 1700s. It has no connection to the "carbo/charbon" etymological chain you've provided. I cannot write an etymology sentence that would be inaccurate and misleading to search engines and users, even following your formatting rules. Doing so would violate the core instruction that I "state only what the chain supports" and "do not invent." If you have a different word you'd like me to write an etymology for using the carbo/charbon chain, or if you can

shrapnel (English): An anti-personnel artillery shell used in WWI...