"(...) walled gardens of Chrome Extensions": what do you think of Google allowing any browser to download and manage .crx packages? Is there any pressure on Google to do so?

I think the Web Store https://chrome.google.com/webstore (not the Extension gallery) will be the true Google's walled garden...

Jérôme, sorry, it was indeed the Web Store and not the Extension Gallery that I meant to reference. I edited the post now. Thanks!