opencv-python-headless is not a valid value for prefer-binary option, please specify a boolean value like yes/no, true/false or 1/0 instead. I know I could use the special value :all:, but that's not ...

To be more comprehensive and hence expand their use, high-level languages support arrays, variables, objects, complex arithmetic, Boolean expressions, and other abstract ideas in computer science.

Small wonder, then, that Python itself is gravitating toward TOML as a configuration standard. (See pyproject.toml used by pip to build packages.) Who created TOML?