Well, never mind. I found it:
unsigned long NTPClient::getEpochTime() {
return this->_timeOffset + // User offset
this->_currentEpoc + // Epoc returned by the NTP server
((millis() - this->_lastUpdate) / 1000); // Time since last update
}
In between getting the time from elsewhere, the local process just uses millis().
Missed that reading quickly time after time, so. I blame the formatting of the expression forming the retune value. Yeah, that's the ticket.
a7