This picture shows an example of the 'Frames' pane in PhpStorm while in debug mode:
I have not found any explanation of the colours in the PhpStorm documentation and I wanted to know their meaning. Why some are green, other yellow and most of them white? Does anyone know it?
Those should be colors from File Colors settings (applies not just here, but in many other places where files are involved, e.g. Project View panel, Navigate To File, Search results, even editor tabs -- all depends how you have configured that).
Based on your screenshot you have default colors for 2 default built-in scopes:
vendor/
folder).You can add your own colors: just define custom Scope that will include certain files/folders (exact or pattern based match), save it and then add a color entry.
Check these links:
Play with those and see how it works / what the changes you will get.