Dear Mr. Fixit: what’s under this carpet?

Dear Mr. Fixit:

Hi! We are debating tearing out some carpet (it’s about 6 years old, installed by previous owners).

Not sure yet if we will replace with new carpet or refinish whatever is under here. It’s in the attic so the quality of the plywood is probably questionable.

I wanted to take a peek at what’s under here and noticed that under or bordering the rug pad, there’s like an orange substance. Is this some type of glue that hardened? It’s all chalky and break apart easily. I knew it would be messy to rip up a carpet but this looks like it would be a pretty epic mess.

We would ultimately hire a professional but I’m still curious about what’s underneath. Pic below.

Thoughts?