Hello,

As you noticed we added in 6.1.1 many mew keys, like
_x_minute_ago
_x_hour_ago
_x_day_ago
_in_x_minute
_in_x_hour
_in_x_day
and others ..
and values here :
{0} Minute{1} Ago for example
{0} mean just a digit
{1} here is - ending of the minute-word (it present in some languages .. in english we can use 's' here .. in another languages - another endings .. so this is just for better localization
in another key values {} mean just a digit - value