Net::GPSD3::Return::Unknown::Timestamp(3pm) on Linux

The text f1ebc6bcfeeb, as Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie), Debian 7 (Wheezy) shipped it.

Net::GPSD3 Return Base Class with Timestamp

Net::GPSD3::Return::Unknown::Timestamp(3pm) on Linux now