Clarify what `red` color means `output will be in this color`

#### Description

At the beginning we can see:

But what does red color means it was not described.

Print info what `red` color means.

No file or test is named. Start by locating the output or help text that produces the red `output will be in this color` line, then identify where its meaning should be explained. Done when the documentation clearly states what the red color represents and the displayed output is no longer ambiguous.

Written by the indexing model from the issue text.