Hi Sasha
My best guess is it needs to be compiled. I think it's all
JavaScript.
According to the From Source instructions in your link, you
will need the npm command. Depending on version and
architecture, you will ether have to install npm.tcz or
node.tcz. It seems they were once separate but now are not.
Try installing npm first. If it fails, install node.
unzip the archive. Then (from the From Source instructions):
cd deltachat-desktop-main
npm install
npm run build
npm start
I can't tell you what happens after that.