The combination of numbers is something called an IP address. It is how the internet knows where to send information. Some wikis do not require users to register an account to contribute to the wiki. If a user makes and edit without creating an account, they are referred to as an anonymous user (or "anon" for short). However, the edits they make still need to be tracked. As such, the wiki uses their IP address instead of a username.

They are users that are not signed in on a Fandom accounts (or they don't have any registered account to use), which is why their IP is showing.