angular/code.angularjs.org — pull request #9 by philwestwell (2014-05-24 11:14:00+00:00)
Title: Update ng.directive:ngAnimate.html

Grammar - Depending on what the author meant, I think the sentence would be either
"It affects how the directive will perform DOM manipulation." (it influences how the DOM manipulation is done)
or
"It effects the DOM manipulation by the directive" (it carries out the DOM manipulation) but not
"It effects how the directive..."
Proposing the version that I think reflects the author's intentions.