Gas line
That’s got to be a homeowner install.
As long as there are homeowners, there will be a need for inspectors! 
No, no, I think that’s okay because they used “caution” yellow. :roll:
This was actually done by a HVAC company. I spoke with the owner and he said that the installer misrepresented his qualifications and has been fired. He also sent a technician to correct the issue the same day I informed him of the problem. I guess that’s good!
The only thing missing is corrugated aluminum venting.