This rule finds text that matches the specified RegEx pattern, and replaces it with another string. (RegEx is short for Regular Expressions).
The RegEx syntax is explained here.
The parameters are as follows:
|Expression||RegEx pattern to match (find).|
|Replace||RegEx pattern that replaces the found pattern.|
|Skip extension||If this check box is unselected, the extension will be included in the rule.|
Tip: ReNamer users have posted many RegEx patterns at the User Forum. You can copy and use them.