Hi,
It is probably closest to a mineral LHM type product but my research via the web has told me that nobody claims to make a product to meet the Toyota spec.
If it helps I buy mine from Milners it's worked out slightly cheaper than from Toyota.
I have used 5lts in the last 3 years doing one complete flush as a baseline service (the original fluid was horrible) and I did a second mini flush a year later, the fluid held in the tank stays cleanest but near the spheres at the working end it seems to darken quicker, I just added a litre or so to the tank and let some out the bleeders to keep the system tip top.