OpenGEX

The Open Game Engine Exchange format is a text-based file format designed to facilitate the transfer of complex scene data between applications such as modeling tools and game engines.

According to the website it was created in 2013 by Eric Lengyel.

In 2015 Khronos Group developed the glTF format which fulfills much the same purpose.

The website compares glTF and OpenGEX, as well as the legacy format Collada.