Not to worry DoN,
IIRC it was an old version of Netscape's email. Someone in their lot had chosen to include an option for how quoted text was to be displayed, and the size of it.
That option, sadly, departed with one of the "upgrades".
AFAIK, it had no effect whatsoever on the outgoing product. I think it just looked for the indicator that text was quoted, and if it found it, it shrunk the text size for that line.
Worked pretty well, as a lowtech answer to trying to sort through the long and unpruned, or the interleaved answers.
Cheers Trevor Jones Happy New Year all!