It's definitely a double braid. I'm guessing it's a full polyester rope. Looks like Stable Braid with that one blue tracer.
I can't tell from the pictures, but is there any glazing in the fibers? That' can be a sign of over loading- though just because there is NO glazing, doesn't mean that it WASN'T overloaded.
If it was my rope, after doing with it what you've described, I'd retire it. You had a good run with it, you got your money's worth, now it's time to cash out while your ahead!
I think we should put a splice on each end and throw it on the testing bed. When is the TreeBuzz getting a break-test bed?!?!?!
love
nick