[...] The manual clearly only goes to 20kHz.
That's because the frequency response is reasonably linear at all levels up to (only) 20KHz. They are Fluke, not FNIRSI.
Not one of the lines is "flat until over 100kHz".
The line at 1.98V is pretty darn flat.
I quickly checked a few datapoints from paschulke2's curves on my 87V and can confirm that 2Vrms at 100 KHz are shown as 1.71Vrms (-1.4dB). Not bad, indeed.
And my point was that it seems weird that nobody at Fluke's marketing/advertising department would ever mention that it can go over 20kHz, no problem. Other Fluke meters/manuals certainly mention it, eg. the Fluke 87 IV:
That's *exactly* their marketing strategy: buy a Fluke 87IV for VAC measurements over 20KHz to complement your 87V
Joke aside, I wouldn't measure anything over 20KHz with 87V (I have other meters for that), but it's good to know that's an option (with paschulke2's curves in mind).