This diff will //very slightly// increase the text contrast in the default Breeze color scheme, while leaving everything else the same and not affecting the overall look and feel of the color scheme.
I find that this very-slightly-higher-contrast color scheme is radically easier on the eyes for prolonged viewing without having to use the actual High-Contrast color scheme, which is radically different and not as pleasant to look at as the normal one is.
Compare the following two images:
{F3869382}
{F3869383}
IMHO the second one is much clearer and less muddy, and therefore **easier** on the eyes, not harder.
There is some discussion in https://bugs.kde.org/show_bug.cgi?id=381288