The lower right corner of one's own "Responses" tab used to show an icon that linked to an RSS feed for "the 30 latest comments, answers, and revisions to a user's content". For profiles of others it was not shown, but nevertheless available manually.
The latter still works, but I can no longer find the icon and its link.
I'm tagging this as bug as I assume it was lost in action when the new user profile was introduced in November 2011, just like
<link rel="alternate" type="application/atom+xml" ...> was lost shortly. But maybe it was removed on purpose, or moved to a place I didn't look?
As an aside, I know Jeff stated:
To be brutally honest, we are moving away from RSS to more email and web-based solutions to some of these things these days -- like newsletter subscriptions and tag subscriptions.
To be clear, RSS is still there, and it's not going away any time soon [...]