- https://en.wikipedia.org/wiki/Antonomasia
>In rhetoric, antonomasia is a kind of metonymy in which an epithet or phrase takes the place of a proper name, such as "the little corporal" for Napoleon I; or, conversely, the use of a proper name as an archetypal name, to express a generic idea.
- https://en.wikipedia.org/wiki/Metonymy
>Metonymy (/mɛˈtɒnəmi/)[1] is a figure of speech in which a thing or concept is referred to by the name of something closely associated with that thing or concept.
Docker-agnostic-file
But seriously, how about: OCIMakefile
I've mostly used nspawn stuff for non-docker containers and then I either build them via normal makefiles that construct the image or I use mkosi.
In the wild, I've seen (case insensitive) Dockerfile (obvs), Containerfile, and Container.