According to research by user OatmealDome on X, the project under the internal codename Owl runs on the ModuleSystem engine. Nintendo EPD used it when creating Tears of the Kingdom and other in-house games. However, the discovered data points to a closer connection between the two installments of the series than just a shared engine.
Modules related to the chemistry engine, which is responsible for a significant part of the gameplay in Breath of the Wild and Tears of the Kingdom, were found in the remake's files. The dataminer also uncovered leftover references to the ancient Zonai civilization, which played an important role in the plot of the latest game. Among other findings is the Korok Forest, familiar to fans of modern Zelda games.
OatmealDome acknowledges that ModuleSystem has become Nintendo EPD's standard engine. At the same time, other games from the studio built on it do not contain references to the Tears of the Kingdom code. Therefore, he believes that the Ocarina of Time remake utilizes groundwork from the previous installment.
ModuleSystem is currently EPD's standard engine, but I still believe OoT was built on top of TotK, as you can find many elements from TotK in OoT's code.
The Legend of Zelda: Ocarina of Time Remake was released on November 5, 2026, exclusively for Nintendo Switch 2.