There is some good information at:
https://www.cambridgeincolour.com/color-management-printing.htm
It gives a good overview of the whole color management topic (it is not specific to Krita).
Here in the krita-artists forum are:
and
Regarding Firefox color management settings - I put together what I found about it over the time - actually Firefox has some kind of color management:
Type:
about:config
into the search bar to get to those settings.
