I've done some in-game tests, with g_debugdamage 1.
It turned out it's a little different than simply doubling the damage (I don't know how to read that code exactly,
maybe it makes the game consider you fell from the double of the real height?).
You know usually, depending from the height you fall down (or from the vertical speed at landing?), you get no damage, 5 damage, or 10 damage.
Tried landing ducked, I've seen I have suffered 5 (or 10, if falling from a little higher) damage from "medium" heights where I would have got
no damage if landing normally.
I have suffered 10 damage landing ducked in places where I usually would have got 5 damage (double).
I have suffered 10 damage landing ducked in places where I usually would have got 10 damage (probably, the limit that prevents a single fall to cause more than 10 damage even if you fall down from a skyscraper still applies).
Hence, the 10 hp damage is still the upper limit, but it's much easier to get that damage!
UPDATE: Just done
DO NOT LINK[/b]) h t t p s : / / openarena . wikia . com/index.php?title=Manual%2FControls&diff=14025&oldid=13729]this update to the wiki, is it ok?