He didn't get 6 figures like the rumor suggested but it might end up being 5/80. The contract is rather complicated, but the gist of it is
He's getting 2/30 over the first two years. After year 2, the Cubs have the option to lock him in for a 5th year for a total of 5/80. If they refuse, Imanaga has the right to elect free agency. If both the Cubs refuse and he refuses to exercise their options after year 2, they will get the same chance to exercise those options after year 3 again. So if Imanaga is good, it's 5/80, if he's bad, it's 4/53, if he's decent enough to elect for free agency but not good enough for the Cubs to want to give him the 5th year, he will either be a free agent after 2/30 or 3/46.5.