I think they are referring to rev hang that occurs in newer manual transmissions where the ECU is tuned to not drop revs quickly for emissions reasons. This makes for an annoying 1st-to-2nd gear shift because the driver must wait a long time between shifts before engaging the clutch in order to shift smoothly. Mostly only newer MTs do this - some worse than others.
That's fascinating. I had a manual hire car this summer and I kept getting the 1st - 2nd shift wrong and juddering - I was wondering why I suddenly couldn't shift well (I've exclusively driven manuals for years, so it wasn't as straightforward as being out of practice). I wonder if that was why.
