What are you thinking.
The wire type, wiring, breakers. 
Oh No! The dreaded FP’s
Yes, Christopher, the dreaded FPs . 
This is the first panel I had seen that had a wire nut used in it. This is very minor compared to the other electrical issues this house had. It seems like something that probably has no major consequence but wanted to make sure.
Christopher, it is ok to use a wire nut in a panel, appropriately.
What would be an inappropriate use of a wire nut in a panel?
If you stuck it up your nose! 
An appropriate number of wires in the correct wire nut size.
For example:
What is your question.
Thank you, George.
Thank you all for the help. I will make sure that I keep the wire nuts away from my nose in the future.
When I was working with an electrician back in the 70’s in noisy manufacturing plants, we would use wire nuts as ear plugs!
LOL! Just messin’ with you.
Splices are permitted in panels. The relevant NEC section would be 312.8.