Fmlib_browser.TimeSourcePosix Time
Posix time is the number of milliseconds passed since the beginning of the unix epoch i.e. since 1.1.1970 in utc i.e. universal coordinated time.
In order to get the time in your time zone you need a time zone.
In order to get a year, month, ... you need the utc time and the time zone you are in.
day_of_month time zone The day of the month of time in zone.
First day of the month is day 0.