Dear Maintainer,

   * What led up to the situation?

Comparing the formatted output of "man" for two files.

   * What exactly did you do (or not do) that was effective (or
     ineffective)?

man fileA > fileA.out

man fileB > fileB.out

diff fileA.out fileB.out

   * What was the outcome of this action?

No output from "diff"

   * What outcome did you expect instead?

Showing the real difference in the output of "groff".

-.-

man falsifies output by squeezing multiple empty lines to one

  This should never have been made as it is still active although the reason
for it has vanished.

  And the supposed reason resulted in a change for _all_,
just because one or few were (and still are) unable (unwilling) to make
local changes for themselves only!

Control: retitle -1 man-db: consider no longer squeezing multiple blank output lines
Control: forwarded -1 https://gitlab.com/man-db/man-db/-/issues/22

"Falsifies" is condescending exaggeration.  man(1)'s contract (such as
it is) doesn't oblige it to precisely pass through the output of
groff(1).

https://gitlab.com/man-db/man-db/-/issues/22 is essentially the same
issue, though I'd see it as a possible code simplification rather than
as a correction.