Fire power 2.95 bug
It is actually an x.x5 power bug. If you look at the history of BasicSurfer/Code, you will see that the old method of comparing bullet powers to filter onHitByBullet to match to the correct wave multiplied both by 10, rounded, then checked for equality. This meant that due to rounding errors, some values of bullets with the pattern x.x5 would not be matched and the bot would not learn from the bullet hit. Since many bots used BasicSurfer as a base, this actually caused a noticable increase in rumble score.
Yeah... IIRC I was doing some extensive default bullet power testing and found that 1.95 drastically outperformed both 1.94 and 1.96 in a large test bed and this turned out to be why. I felt kind of dirty since I was both the person that introduced the bug and the one who figured out how to exploit it. :-/