KB Article:

A wildcard is a character that can be used as a substitute for any of a class of characters in a filtering parameter, thereby increasing the flexibility of filtering.

In filtering parameters, you can use the following metacharacters:

• Asterisk ( * ) - Matches any string of characters. It can represent zero characters, all single characters or any number of any characters.
  
  You can, for example, display all files with the extension "exe" and only them by typing "*.exe" in Include parameter (such filter will not display files with the extension "exec").
  
  "svc*" matches files which are prefixed with "svc" such as svchost.exe but scsvc.exe or test.svc will not be displayed.
• Question mark ( ? ) - Matches any single character (exactly one character). Thus, two question marks in succession would represent any two characters in succession, and three question marks in succession would represent any string consisting of three characters.
  
  For example, "app??.exe" matches app34.exe and appex.exe files.