Documentation about versionless component is incorrect
A versionless component is one where the version does not appear in the URL. To make a versionless component (or make one of the versions of a component versionless), the name of the component version must be "master". If the version is master, Antora remove the version segment from the output path. However, the version "master" can still be referenced in resource IDs.
If the version has any other value, it will appear in the URL. The documentation needs to be clear on this point.