hnlinks v0.4.1
This extension adds a sidebar to comment threads on news.ycombinator.com which collects all the external links from comments and allows you to quickly jump to the context from a link. If a link has been posted as a HackerNews story before, you can see that too.
Toggle the extension by clicking its button on the toolbar or the shortcut Shift + Alt +8. You can customize this shortcut from the Manage Extension Shortcuts menu from the addons settings page's gear icon.