BOSTON — The 1964-65 Boston Celtics had “Havlicek stole the ball!” The 1980s Celtics had The Original Big Three. The 2007-08 Celtics had a new big three and an exciting new rallying cry: Ubuntu.And now, Celtics fans, stand up, put your hands together and cheer wildly for … optionality!Brad Stevens, president of basketball operations for the Celtics, used that word so many times Monday that it kept reminding me of that time former Philadelphia 76ers guard Allen Iverson kept talking about “practice.”Stevens was speaking at a much-anticipated, packed-pews news conference at the Red Auerbach Center to talk about the wheeling and dealing he did last week, which included the exodus of longtime Celtic Jaylen Brown to the 76ers for forward Paul George, a 2028 first-round pick, a 2031 first-round pick and two second-round picks. The deal includes some codicils involving a “pick swap” in 2028 that even Stevens said was “super complicated,” something “we don’t really need to go into here.” So we won’t, other than pointing out that you can read about it here.Why did the Celtics trade Jaylen Brown?Jay King and Jeshua KiddBut if the ever-calm but admittedly sleep-deprived Stevens was hoping these words would be an off-ramp to an easy-to-digest explanation for why Brown no longer is a Celtic, he struggled in that pursuit.The summary paragraph in Stevens’ explanation is “the path looked a little bit more challenging with 70 percent of our cap and such a high percentage of our usage tied into two players.” Those players are Brown, whose five-year, $285 million deal runs through 2028-29, and Jayson Tatum, whose five-year, $313.9 million contract runs through 2029-30.Stevens brought up the new collective bargaining agreement and the good old days when “47 percent of the cap is what those two guys were when we won it all.” Where it gets complicated is the Celtics’ contention that this was not … wait for it, wait for it … about the money. Bill Chisholm, the new owner of the Celtics, seated to Stevens’ left at the news conference, said as much.“This was trying to put together the right set of players and assets to win now, and then next year, the following year and the year after that,” Chisholm said. “That’s what this was about. None of these were about money. We have some room now if we see something we want to do.”