I noticed down by my fuse panel, this connector was just laying on the floor not connected to anything...Is this for diagnostic purposes?

 

I had the same post a little while back.
It is definitely not the the Cordiestrecker or diagnostic Code Plug.
A trustworthy Post said it was 'for the O2 pot if you don't have cats'.

Not to concerned in that I have 'cats' and my car runs great.
Must be one of those things that you'll find, but never need like the third fog light switch harness tucked in the pod.

 

Sounds good, thanks for the quick reply.