There isn't, and it wasn't used for valuation. The number appears nowhere in the purchase document which assigned the valuation; nor does any reference to it. It could be 20%, or 50%, and it wouldn't have any bearing whatsoever on the purchase agreement.

Musk agreed that the number of bots not currently being caught was probably higher than 5%, which was a big part of his stated reasons for buying Twitter. Then the market took a turn, and now up is down, Musk is pretending this number matters.

It doesn't.