How does GPS on the adafruit ultimate hat handle leap seconds?

I haven’t been able to find much information on how leap seconds are announced when using gps with a adafruit ultimate hat.
So for a future leap second, how would my server get that there is a leap second?

ah gps and glonass both broadcast a gps-utc offset, which I’m guessing would be changed on the leap second.

I don’t think there’s a way to get the current or future leap seconds from the Adafruit GPS (MTK3339), so it doesn’t give you a notification of the upcoming leap seconds. There are some vendor specific GPS receivers that do give this data.

I believe the common output during the leap second is to show :60 as the seconds, such as this example from leap seconds “$GNZDA,235960.00,31,12,1998,+00,00*50”

chronyd can leap seconds from the system’s timezone database, and ntpd/ntpsec can get leap seconds from the “leap seconds file” The NTP Leap Second File [Knowledge Base]