W3C widgets dead?

Question

Someone recently directed me to the W3C specification for widgets:

http://www.w3.org/TR/widgets/

Developers can disable web applications offline through the browser cache. I asked how users should know that they can use certain websites offline, namely when the user raised the widget specification. It makes sense to split application packaging apart from the stand-alone storage ability. However, after searching and reading on widgets, I could not find the latest articles on this issue (most of the articles seemed to be around 2010). In the end, I found the Opera SDK, but in the beginning I got a message saying that they removed the functionality:

Starting with Opera 12, Opera widgets will be disabled for new users and completely removed in a later release.

source: http://dev.opera.com/articles/view/creating-your-first-opera-widget/

Are W3C widgets dead technology? And if so, is there any cross-browser technology for packaging web applications? I am curious because I think that offline storage is interesting, but I don’t see how users will know that even when they don’t have an Internet connection, they can view a specific URL and work if the browser didn’t tell them which applications they are installed (or if each site supporting offline storage explained to them).