Make it easy to find/download compatible extensions.
So I went to https://extensions.gnome.org/ and tried to find an extension for CPU monitoring. So I typed "cpu" in the search box.
The top two results were "CPU Frequency by ojo" and "CPU Freq by bokal", which are both ancient; targeting 3.2 and 3.4/3.6 respectively. And user reviews show that they indeed do not work on modern distros.
So "Compatible with Current version" rather than "Compatible with All versions" is probably a better default? (When current version is available).
Side note, it is not clear/obvious whether "Download" is meant for pure download or it would affect the installation to current shell as well. While we are at it, why don't we mark the current shell version in "Shell version ..." (when possible) and sort "Extension version..." in descending order.
My apologies if similar concerns have been raised already.