Last modified: 2013-08-19 17:45:59 UTC
As of Aug 19: On beta labs and mw.o the preference for Preferences/Appearance/Advanced/Enable "jump to" accessibility links" has disappeared. The preference still exists on enwiki
It was intentionally removed in Ib506ffad41ac7f65629368bc41774fb689b882db. "Jump to" links are now always present in page source and hidden via CSS.