A community-collated hub for all things RimWorld Modding.
It doesn’t matter which you use, as long as it isn’t notepad.exe, Microsoft Word or Libreoffice.
Here’s a list of good text editors.
Try them out for yourself and see which fits.
All of them have one critical feature which you will use a lot:
Folders as workspaces and “Find in Files”. Open
Core\Defs as a workspace and it adds an explorer-type filetree to your windows. You can then search all the files inside that folder and its subfolders. Need to find all occurrences of “
<costList>”? Find in files has you covered. This is by far the most useful feature, and it will greatly increase your efficiency.