A comment in an enhancemente request posted last year said about the style:text-line-through-color option.
There is no (i don’t find) UI to modify it.
There is a known way to add it manually? May be editing the content.xml file?
There is no (i don’t find) UI to modify it.
Sure - the enhancement request you linked to is still in state “NEEDINFO”, which implies it is not yet implemented and using style:text-line-through-color attribute in content.xml had no effect (seems to be silently ignored) in a short test.