If you wanted to publish your activity in GitHub somewhere and your preferred way was to read an old, friendly RSS feed, I have some not so good news for you.

It is possible to get and RSS feed, but you need to send the adequate headers, as stated in Feeds.

curl -H "Accept: application/atom+xml" https://github.com/security-advisories

This means that it won't be easy to get these feeds in your feedreader (as far as I know they won't allow to modify headers and, for example, the excellent Feedly does not use this trick).

But if you want to insert this in a program it should be easy to do (in Python, for example, you could use feedparser module and, in Other HTTP Headers they explain how to do it).

For example, for the activity of yours truly, you could use:

d = feedparser.parse('http://github.com/fernand0', request_headers={'Accept':'application/atom+xml'})

Et voilà:

d.entries

has the content available in the feed.

Let me know if this is of some utility for you.