👍

But maybe instead of separate page, some (maybe animated) pop-over or iTunes-like sliding pane?

I first also thought about revealing this info via an animation, but it has a couple of drawbacks:

• harder to implement
• harder to get right for specific use cases like disabled JavaScript or accessibility
• a dedicated Installation page will have an URL, which you can share

harder to implement

Hmm (not tested)

document.getElementById("download-stable")
    .addEventListener("click", function(e) {
        document.getElementById("download-pane").classList.toggle("visible");
    });

and then some CSS Transition magic 😄 HTML5 is awesome!

harder to get right for specific use cases like disabled JavaScript or accessibility
a dedicated Installation page will have an URL, which you can share

Hmm, what about mixing these two approaches? Download page's contents will be put inside a partial template. It will be rendered as an animated pane on the front page and as a separate page. Download button will point to that separate page. Two birds killed with one stone.

Yep, this is the best approach.