User blog comment:Rappy 4187/Technical Update: March 5, 2013/@comment-4625170-20130307215911/@comment-452-20130307221250

I concur, the "Followed Pages only | See all activity >" links at the top of the page, shown in the screenshot on Admin_Central:Guide_to_Wiki_Activity have been replaced with "Special" page.

MediaWiki:Oasis-page-header-subtitle-special is what is currently being shown.

The normal text is stored at MediaWiki:oasis-button-wiki-activity-watchlist and MediaWiki:Oasis-page-header-subtitle-special-wikiactivity or MediaWiki:oasis-button-wiki-activity-feed. (Just the text, not the links)