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.
\w+_
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.