Here, put this in an executable ~/.byobu/bin/100_uname:
#!/bin/sh printf "\005{= bw}%s\005{-}" $(uname -r)
The \005 is the escape sequence.
{= bw} says blue background, white text.
{-} says undo the last color change.
See the screen(1) manpage, search for "Colors" to find color codes.
Here, put this in an executable ~/.byobu/ bin/100_ uname:
#!/bin/sh
printf "\005{= bw}%s\005{-}" $(uname -r)
The \005 is the escape sequence.
{= bw} says blue background, white text.
{-} says undo the last color change.
See the screen(1) manpage, search for "Colors" to find color codes.