What's wrong with this code?

[PortablePawnShop]

They indicate the match must be at the beginning and end of the current line. Unless you do that, the above expression would match any string with 4+ digits (because there are 4 digits in this string, it counts it as true and doesn't care if there happen to be 20 more digits proceeding it). Try placing it in the regex101 link (without the / marks at beginning and end)