Looks like silicone.  Just buy a tube of it and fill in the gap

It’s not glue - just silicone to try to keep it weatherproof

No sir. Remove it. Clean it. Buy some outdoor rated caulking. Apply it. Repeat every 12 years.

That's another type of silicone most likely.  It's dyed and such to give it a blended color

The one on my house looks like a greyish/black clay putty.  What type of substance is usually used for this other than silicon?

I’ve seen people use expanding fire proof spray foam instead. Not exactly the way I would do it, but I’ve seen it done.

Lol. Op thinks it’s glue holding it in place 🤣🤣🤣

Glue holding AC hose has come loose