Shiny Black Primer?

What exactly kind/type of formula was used where the factory painted stuff black like we find on seat tracks, sheet metal, and other stuff that, as far as I can tell, was applied without a primer coat? It seems to have held up fairly well, all things considered (photo #1 has been sanded, photo #2 has not been prepared yet).

View attachment 1715733912

View attachment 1715733913
I believe that type of painting is called, in the painting trade, "DTM", meaning "direct-to-metal". If the metal is newly finished, dry and clean, the paint adheres relatively well enough.