Exponential Platform is the Symfony based family of Exponential: the free continuation of eZ Platform and Ibexa Open Source, maintained by 7x for current PHP. It comes in three distributions: Legacy (a Symfony platform with the Exponential 6 kernel inside), Nexus (a finished website with Exponential Layouts and demo content) and DXP (Symfony only).
Its Confluence section keeps the former documentation center of the 5.x era as it was: one section per space (the Exponential 5.x and 5.1 manuals, the eZ Platform developer, technical and user documentation, the FAQ, the glossary and the others), and the page copies, histories and lists of that export.
All distributions at a glance: github.com/se7enxweb, and the help center's guide Distributions of Exponential.