A dismissive way to refer to vague, unspecified things or to speech that is diffuse and lacking in concrete information; 'this-and-that' or 'who knows what.'
Examples:
ES: No lo sé. Ella puede decirte, pero siempre habla en esos mi-no sé qué y no sé cuánto es eso.
EN: I don't know, she can tell you, but she always talks in those kilo thingies, and I don't know how far that is.