It looks like AME412. That's the same cable they use OSP. There is no rhyme or reason why they run some like this and some with insulation.
I think the first "fire retardant" telco cable was lead sheath.
It didn't burn....but the contamination was another thing.
In Pittsburgh, there is, literally, thousands of pounds of lead sheath cable still in use as OSP, in building riser and protector tails.
Rcaman
