Are tirthankar born in dwapar or treat?
According to Jainism, Tirthankaras are born in every time cycle (kalachakra), which is divided into six aras (epochs or time periods) in both Avasarpini (descending half) and Utsarpini (ascending half) of the time cycle.
The terms "Dwapar" and "Treta" are from Hindu cosmology and refer to yugas (ages), but Jainism has its own time measurement system. In Jain cosmology, the current time is considered the fifth ara (pancham kaal) of the Avasarpini (descending cycle). The 24 Tirthankaras of the current cycle, including Lord Mahavira, were born in the third and fourth aras (sushama-sushama and sushama-dukhama).
So, in Jainism, Tirthankaras are not specifically associated with Dwapar or Treta yugas, but rather with the Jain time cycles and their respective aras.