Sync (aka Din Sync) is a completely different (additional but older) music machine protocol to MIDI … it can send clock anda kind of ‘transport’
You’ve misread, misremembered or been misinformed - MIDI thru is strictly only a copy of the physical/DIN plug MIDI In data
Almost every MIDI box works this way to be fair
Yes, this is why it is helpful as per guidelines to search before posting (keeps it tidy), issue discussed a lot, due to the mixing up of terminology, there’s MIDI Clock MIDI Timecode MIDI Song Position Pointer but no MIDI sync afaik - DIN Sync predates MIDI
It’s possibly misleading to be fair, but the manual is clear
https://www.elektronauts.com/search?q=thru%20sync%20%20%23elektron-gear%3Aanalog-rytm