Are the Flanking rules gone?

A search for flanking no longer finds the optional rule description.  It is on page 251 of the hard copy DMG.  But no longer found on DNDBeyond DMG.

They're still there! https://www.dndbeyond.com/sources/dmg/running-the-game#OptionalRuleFlanking

So my first impulse was to respond with, "They're right behind you!" Is that wrong?

 The search on this site is notoriously bad. I searched 'flanking' and the 9th result was 'Using Miniatures,' but it included optional flanking rules in its preview, even though that's about a page or so after Using Miniatures starts.