Notepad++ user defined language file for Log4Net syntax coloring.
Original post: Colored log4net log files in Notepad++
TL;DR
Simple way: If you have never defined of modified a User defined Language, you can simply download the file at src/userDefineLang.xml and override your existent in %APPDATA%\Notepad++ (Make sure you backup your file first)
"Harder way": if you have modified or added a user defined language, you probably know what to do but anyways, download the file (same from above) open it in your favorite text editor ;) and copy the UserLang tag with its content and paste it to your current userDefineLang.xml file.
Enjoy!