See [.NET](https://github.com/openactive/OpenActive.DatasetSite.NET/#feed-level-customisation) and [Ruby](https://github.com/openactive/dataset-site-template-ruby#feed-level-customisation) libraries for examples of this - it's implemented but not documented within this PHP library.
See .NET and Ruby libraries for examples of this - it's implemented but not documented within this PHP library.