Extensions are only supported in CommandTimer v6 or higher.
This is not a plugin. It should be installed inside the CommandTimer folder (CommandTimer/extensions) and not inside the plugins folder
Installation:

- Download the jar file
- Drag & drop the jar file in the extensions folder (plugins/CommandTimer/extensions)
- Reload/restart
- You should now see the new extension in the conditions menu

Available conditions:

• Check if user is in region