This command will fail to refine an item in the specified equipment slot of the
invoking character. The item will be destroyed. This will also display a 'refine
failure' effect on the character and put appropriate messages into their chat
window.

The official scripts seem to use the 'failedrefitem' command as a function
instead: 'failedrefitem(<number>)' but it returns nothing on the stack. This is
since jAthena, so probably nobody knows for sure why is it so.