Why can default settings of character style not be modified?

Libo 4.2.6.3 on XP

I tried in Writer to modify the default settings of character style in Styles and Formatting tab Character. When right clicking on “Default” there is only the option “New” and “Modify” is missing completely. “Completely” means it is not not greyed out but just not visible.

Read my explanation in Why definition of a character style "relative" to the "Default Style" is blocked? - #5 by Regina

@Regina Thanks for the excellent explanation. I left a comment there as well.