Comprehensive Guide for Developers: UI & SDK Integration, Configuration, and API Reference
How the pages were laid out (continuous, facing, …).
Zero-based index of the page in view when the document was closed.
The fit the zoom came from, so "fit width" stays fit to width on a resized window.
Zoom factor at that moment — 1 being 100%.
Where the reader had got to in a document, kept so reopening the same file resumes it instead of starting over. Written when the document closes, replayed when it opens again.