Press alt + numeric in bash and you get (arg [numeric]) what is that?

Question

Press alt + numeric in bash and you get (arg [numeric]) what is that?

(This type of question is better suited for asking a human, instead of trying to \"guess\" for the

Answer 1

I don't know but when you do alt + numeric and then you press a character, you'll get num caracters: (arg: 123) + a -> 123 times "a"