We just upgraded to Jenkins 2.249.1 from 2.190.3.
Some of our users are complaining that the stage log headings are too dark. I tend to agree, and the blue font is really hard to read on top of the dark gray.
This is not critical, and I love Jenkins a lot, so I hate to complain. But it would be nice for the default theme to be easier to read in this regard.
If I try the Dark or Solarized themes this improves. This is only a problem with the default theme. Some users prefer the default theme.