[texhax] cmr vs lmr width differences

[Karl Berry]

    Is this difference intended?
    \hbox{f\/}
    cmr10: 3.83336 pt     lmr10: 3.8477

    Without the italic correction both fonts yield 3.05557pt

I expect it is, yes.  lmr10 was never intended to have the same metrics
as cmr10.

As for the particular change to the ic of f, I expect that the slightly
larger number simply looks better.  If in doubt, try making proofsheets
with gftodvi or fontforge or whatever, or look in the LM logs to see if
it was ever explicitly mentioned.