aria-current is placed on the link or item representing the user’s current location, page in a breadcrumb trail, active tab, current step in a checkout flow, with a value describing what kind of current it is, such as page, step, or location. Screen readers announce this so users know where they are without relying on a visual highlight alone.
It is a lightweight fix with outsized impact: many sites already highlight the current nav item visually with color or an underline, but never expose that same information programmatically.