FlagCountLowerBound(FlagCountLowerBound)
One flag's share among movements that could be attributed.Used instead of FlagCount whenever the breakdown is a lower bound. Two
independent causes: the side's count itself is inexact, or the count is
exact but at least one counted movement had no readable flag. Exact
count beside top_flags_lower_bound is legitimate; what is inexact
is the flag distribution, not the count.
{
"flag": "SG",
"vessels_lower_bound": 3
}