This system variable can be useful when trying to make mods using owo-lib working with mods like PolyMC.
I get that it's not an intended use of the lib or in the library's focus at all but to someone this can be helpful.
Maybe it can be listed as a unsupported use of the library, the mods using this library and it should be used at your own risk?

Also I haven't looked at the code enough, but I think that any system variable should be at least mentioned on the docs.

Thanks for giving us a heads up about this, there is a now a page in the docs which explains all system properties oωo provides
Cheers