Trusses

Just a question for you all
I did an inspection last night and stamped on the trusses in black ink was the word Fire-ex with a picture of a little man in a running position, this was stamped on all of the trusses, I have never seen this before, has anyone else? it was a townhouse year built 1979. The sheathing was shot, it was deteriorating and falling apart, I did not see any FRT stamps, that is how bad the sheathing was, but my guess is that it was.