The most notable additions will be an interactive search (fully local), an "On this page" table of contents for each page (direly needed for a better overview of the manifest options I think :)), Copy to clipboard functionality for each manifest snippet, and (not visible in the screenshot) access to documentation for previous releases (meaning: when 2.1+ is eventually out and you're still running the 2.0 editor, the documentation links in the graphical interface will still take you to the 2.0 documentation online \o/).

Also: Technically the documentation could (already) be packaged with faircamp releases (it's only ~400kB, uncompressed), allowing for offline documentation access, I just don't have the time resources to adapt packaging for this right now. '^^ (but this will come eventually!)