The default line is now much faster. More risky, more aggressive, and about 7 tenths a lap quicker than 1.0. Still no retirements in a few more tests (less than 1.0), but more than a few close calls. They go for it here. Not much left in the lap - I'd say 5 or 6 tenths for a human, but the AI's limited capabilities are stretched pretty hard here. I'll likely stop with this one.
The 1.0 line, which is safe, reliable, and much more relaxed (and still fairly fast in its own right) is preserved as "fast_lane.ai_standard" in the AI folder. Rename this file to fast_lane.ai to revert to the original safer line.