WP Engine's "forking" consisted of disabling the revisions feature by default. As someone who's personally been bitten by this particular WP Engine misfeature,

WP Engine's "forking" consisted of disabling the revisions feature by default. As someone who's personally been bitten by this particular WP Engine misfeature, describing this as a "fork" is disingenuous at best. The average Linux distro ships way more out-of-tree changes than WP Engine ever did.