The following fastener fell out of a breakfast bar stool. It came loose from the area shown below, where the hole is.
I have never seen a bolt like that, and Google Lens is not much help-- what is it? And can this stool be easily repaired?
Note: I am helping an elderly, internet challenged relative troubleshoot this remotely. I can ask questions and ask for more pictures (within reason, given limitations on mobility), but I can't put my own hands or eyes on it directly until Christmas, when I will be physically present. It is at that time I hope to fix it. If I can figure out how, and what I might need to bring with me.



