When CNBC debate moderators asked Donald Trump why he insulted Mark Zuckerberg in his immigration plan, Trump had an answer that befuddled moderator Becky Quick: "I never said that."
But actually, Trump really did call out Zuckerberg in his immigration plan. His plan says, as stated explicitly on his own campaign website, "This will improve the number of black, Hispanic and female workers in Silicon Valley who have been passed over in favor of the H-1B program. Mark Zuckerberg’s personal Senator, Marco Rubio, has a bill to triple H-1Bs that would decimate women and minorities."
Now, this is noted in Trump's plan, so it's entirely possible he was never aware of what was in a plan that an aide wrote up. Otherwise, Trump seems to be bluffing.
For more on Trump's immigration plan, check out Dara Lind's explainer.