There is a wiki page dedicated to understanding the emerge output: http://www.gentoo-wiki.com/HOWTO_Use_Portage_Correctly "Understanding Portage's Formatted and Colored Output" Maybe a condensed version of that section of the wiki could be added to emerge output when a -vv switch is used. Reproducible: Always
That information is already included in the manpage, no need to clutter regular output with redundant explanations all the time. Or is it really so difficult to read the documentation?