Not JSON - a plain zip archive of one project folder, flat (no subfolders). Includes base.pdf, every *.json/*.js project file, fonts (.ttf/.otf), and image assets (.png/.jpg/.jpeg/.gif/ .webp/.bmp/.svg/.svgz/.pdf/.ico). presets.json is included by default but may be excluded on export.

Generated PDFs are never part of it - they were never in the project folder to begin with. Importing unzips it as a new project folder named after the archive's own filename, collision-suffixed if that name is taken.