They look like some sort of power supply cords, possibly for a built-in massager or heat units.

Someone gave me this chair and I want to sell it, but I don't know anything about these cords coming out the back, or what they're for. It's just a standard black fake leather office chair otherwise. Sorry if I'm an idiot for having no idea what this is about, but I'd appreciate the help so I can maybe bump up the price a little if they, say, activate a portal or some shiz.