In article , "HeyBub"
wrote:

alongside the RG6 the company also ran a much thinner wire, looks to
be stranded aluminum inside a black jacket. Now what would that wire
be for?

Probably not Aluminum; more likely steel.
It is used as a mechanical support for the cable

That is known in the telephone world as "suspension strand". Of the CATV
drops I've seen so equipped, it's a SOLID wire.

Look at the other end of the cable for additional clues.

While it is often bonded to an earth ground at the house, I have never seen
one bonded to anything at the pole.
--

JR