DWV patching material ?

Maybe 50 years ago, the landlord hired a legit plumbing company to patch a leaking sewer pipe from the apartment above. The plumber somewhat cleaned off the cast iron pipe, then made a patch from a dark gray fibrous sticky waxy material, and placed the patch over the hole. He then wrapped the pipe and patch with several layers of vinyl tape.

Anybody know what the material was or where to find it? Local plumbing stores have no idea what it is.

Was it pitch fibre?

What that plumber did 50 years ago was -------rig a fix, and it did not hold over time
the ONLY way to CORRECTLY repair a sewer line is to cut out the bad and replace with new.
NO ONE on this forum will give you the name of some shoddy crap to use.
we are professionals and HOMIE DONT PLAY DAT

Not advocating, just trying to help identify.