Tiny Tools › URL parameter glossary › mkevt
mkevtA "marketing event" flag eBay appends to links that pass through its marketing and affiliate system (you'll usually see mkevt=1). It simply marks the click as one eBay wants to measure. Reporting only — the listing loads fine without it.
Safe to remove? Yes. mkevt is used for tracking and reporting only — deleting it does not change the page you land on. Strip it before sharing a link to keep it clean and private.