Everything on the website here was ported from the game itself--you can see the in-game Hiergamenon entries by clicking the unlocked/subsequent items in the tech descriptions.

You can click through the "leads to" and "requires" options in the in-game hiergamenon to browse the tree.

{And yes . . after playing the game  a few times I can' avoid not knowing.  }

I just checked the in-game hiergamenon. All the techs are arranged in alphabetical order, which means it difficult to read. It should be arranged exactly like the tech tree. In addition, in order to read what does the tech do (what improvements, leads to what, etc), I have to click the tech which brings me to another page.

It will be good to have these information lay out infront of you, just like the hiergamenon on the elemental website, for easy reading. With an overview, we can then plan our research better.