Bonds were stronger to start the domestic session after European bonds led a rally late in the overnight hours. Trading was flat during the domestic morning hours. A big miss is the producer price data was overlooked because--well.... producer prices are almost always overlooked when it comes to market movement.
When Europe closed for the day, US bond yields began to rise, and that's really the truest and most compelling narrative of the day, but things did happen in the afternoon, and the market participants who remained were keen to make much of little.
Of the afternoon market movement candidates, a strange tweet about an off-the-beaten path US/China announcement garnered the biggest reaction (something about Visas being revoked for certain Chinese officials), but it was certainly Powell's speech that got most of the mainstream attention. Simply put, it sounded, for a moment, like Powell was announcing some sort of QE4 program. After all, most of our experience with the Fed expanding its balance sheet (which Powell said was coming) centers on QE.
But Powell was quick and careful to note that this wouldn't be QE. Most traders believed him, even if some analysts and market-related websites didn't. Either way, bonds didn't move in a meaningful way in response to Powell, so that's all the verdict we need on this one. When the next round of actual QE is eventually announced, we'll all definitely know it and it will be easy to see the market's reaction. Today wasn't that day.