The Shiny page about icons says that one of the two libraries they're taken from is the Glyphicons library. That Shiny page provides this link to Glyphicons:
but when I click on that link, I get taken to a different page on getbootstrap.com, the Accordion page (I can't post the link here because the forum complains "New users can only post 2 links" if I try to include a 2nd link in my post... which seems like a bug btw...) but it's the current page for the Accordion component.
When I'm on the Accordion component page, the menu of components on the left doesn't include Glyphicons as an entry.
So does the Glyphicons library still exist?