There are a few types of codes used on this site. The first is Regex related to Claws 7. As much as we try to share them online in a way that can be easily copied and pasted, quite annoyingly, “WordPress” doesn’t like to leave them as they appear.
The backslash “\“, in particular, gets removed and requires the user to type it back in for example. By the way, \w+ equals “any word” and this works with programs like Lawrence Anthony’s concordancer “Antconc” and software that can do search and replace with regex such as “Notepad++” for searching for strings of text or grammar patterns where we need any word similar to a wildcard.