Since Meson 0.49.0, the / operator on strings is equivalent to calling join_paths() [1], and the former is less verbose, and easier to read. [1] https://mesonbuild.com/Reference-manual_functions.html#join_paths https://github.com/containers/toolbox/pull/1141
The file format is TOML[0] but the file extension is .conf to follow the convention set by Podman. https://github.com/containers/toolbox/pull/828 https://github.com/containers/toolbox/pull/851