Yup Th2 is RedStone, 10192 and onwards are GDR1 builds, when RTM officially out, GDR1 builds will then carry the RTM build no. with increasing deltas.
I always think that, th2 is fall update 2015 & fbl_ur1 is Redstone update of 2016. Reason: th2 means Threshold 2 (codename of W10 is threshold), so it should be fall update. fbl_ur1 could mean Update Redstone..
if have it is possible leak and today independs what chinese have in minds for today i can say chinese it 100000% crazy
a lot of people are starting to say 240 IS RTM. Not sure if that means 240 is RTM as 240 or if it means that the code in 240 will be renamed to 400 or something else and THAT is RTM. It seems they are saying 240 as 240 will be it. Interesting.