Who can see my items?

Only members of the groups you have listed the item in. Nobody else, and there is no way to opt into anything wider.

There is no public directory, no map, no "items near you", and no way for a stranger to search Kithage. Someone outside your group cannot see your things and cannot discover that your group exists - a link to a group they are not in returns "not found", not "access denied", so the group's existence is not leaked either.

If you list something in two groups

Both groups see it. They do not see each other, or each other's members.

Worth knowing: where you keep it travels with the item. If you have written "garage shelf" and you share the item into a second group, that group sees it too. That field is only ever shown after a borrow request is approved.

Photos

Photos are served through links that expire, so a copied link stops working. Location data is stripped before storage - see what happens to your photos.

What Kithage never stores

Street addresses. There is no address field anywhere, on purpose.