Hierarchical Event Descriptor (HED) specification
The current version of HED is maintained in the wiki associated with https://github.com/hed-standard/hed-specification
The latest and selected past XML versions of the HED schema are generated from this wiki and stored in the hedxml directory of this repository.
The stable link for software requiring the HED schema for validation is https://github.com/hed-standard/hed-specification/tree/master/hedxml
The stable link for the latest version of the HED schema is https://raw.githubusercontent.com/hed-standard/hed-specification/master/hedxml/HEDLatest.xml