Guard::UI

Parsed documentation:
View on GitHub
The UI class helps to format messages for the user. Everything that is
logged through this class is considered either as an error message or a
diagnostic message and is written to standard error ($stderr).

If your Guard plugin does some output that is piped into another process
for further processing, please just write it to STDOUT with `puts`.
Suggestions:
Please help! Open an issue on GitHub if this assessment is incorrect.