No, that was Firefox. Chrome's spread was fueled by literal malware or spyware bundling it to get some of Google's sweet money and some of the most aggressive advertisement campaigns for any online product ever.
Was it Firefox? I remember Firefox existing at the time but I don't think it's ever really had dominant market share, perhaps when it was Netscape? I do remember the IE campaign went on quite a long time to where eventually Chrome showed up to the party and people shifted over as well as shifted their family and friends over. You don't see that kind of active effort for Firefox ever.
Yes, FF was revelatory (features and performance) and, relatively, very popular for a time. 31% was a massive share considering it was up against a browser that was the default for the vast majority of people using computers.
Mozilla have had so many chances to position themselves as the privacy-preserving alternative in current years but just can't get out of its own way in any sense (e.g. corporate greed or being hostile towards users). There's still dim hope for FF and some of its forks, like Librewolf, but hopefully forward thinking projects like Servo and Ladybird can fill the void.