@Zanna "any number of digits" introduced by the editor was misleading. For example, that expression would catch "abc5x4yx" as well. But if were regex, it would have caught 55x44 only. Anyway, if I consider that as regex, then it is malformed due to the dangling * at the initial place.
@Kulfy what I meant was that the suggestion was wrong regardless of the interpretation, but since the second part of the expression [0-9]* matches any number of digits when interpreted as a regex, I think you are right about the editor's confusion, even though the suggestion was even more wrong than that particular confusion would explain
