Translations / Versions
You can globally switch between versions or translations, or/and compare all of them in situ.
First, choose your main version, using the "VERSIONS" menu always visible at the right; second, for each piece of text, you can easily show or hide these different versions in situ, clicking on the version's name on left top of each enunciation. It can be done with main enunciations (for ex. proposition) and also secundary enunciations (proof, note, corollary, etc.).
Hyperlinks / Browsing
Secondary enunciations - like proofs, notes, etc. - are hidden by default, but listed under their parent : just click on their name to show or hide them.
For each proof or note, etc., you can also show enunciations used by it, clicking on their names : for ex., "demonstratio by 1, def 3 | 1, def 5", click on "def 3" to show it in situ.
Last, "Infra" link lets you see next uses of each enunciation.