The success message that gets output when adding a Stream Highlight (error messages can not be customized). The following parameters can be used:

Example:

Added stream highlight [$(uptime)] $(comment) $if(chatuser,\(This is a mod-only command\))
Compared to default this omits some information, but adds a note about who can run the chat command (but only if actually ran from chat command, note escaping the parentheses as well).