Frustrating isn't it....perhaps a sign of the manuals being "dumbed down" or "why would you need to know that"...
Like you gents a few years back I recall my previous type's FCOM (744) gave the numbers ( and yes, I recall it being something along the lines of below x feet for y seconds).
Not sure if I have ever seen the 777 FCOM with numbers quoted and as
JS states now it just seems to be the narrative as described in our FCTM, FCOM, etc.
I guess all this means it's bound to be a question in this year's tech quiz.......