I'll admit I was confused by this too
I've been using Analog Devices eval board gyros since before the PCB kit gyros were in existence, so I never wired a kit gyro before this year. Another team asked a question about the kit gyro so we wired it up to test its behavior ourselves. When I looked at the gyro, my first instinct was "R" was for "Rate" (it is a yaw Rate sensor) but I asked someone to check the sensor manual. He said "T" was for "Temperature". It made sense so a student wired the "R". We tested it, it didnt work.
The meeting ended and I couldn't figure out what was wrong. I was thinking "some help I am, I don't know how to wire the kit gyro". By chance, I looked at the WPILab doc that night and noticed the "T" was wired. Of course then I realized what was wrong. The next day, we fixed it and all had a good laugh about "Relative Temperature" and "Twist".
We all agreed that the gyro labeling is counter intuitive.