I bought a new doorbell which required me replacing my transformer. My current transformer is attached to a receptacle that sits right below my panel. Turned the power off to it, unscrewed it, found my current transformer wires were backstabbed into the receptacle (and my ground wire was not secured to the ground screw as a nice bonus). My receptacle didn't appear to have a release hole so I tried to tug and twist to remove but both wires ended up breaking off with a small piece of the wire still stuck in the outlet. Below is a photo of that. You can see the broken off (stranded?) wires on the lower half of the receptacle between ground wire and neutral wire. There are other backstabbed wires but also an available neutral and hot terminal on the receptacle:
From what I have read backstabbing is not code unless it's 14 AWG solid copper wire right? These seemed stranded to me. Is it safe to continue using this receptacle if my plan is to attach the new transformer wires to the terminal screws instead? I would also of course make sure to re-attach the ground wire.