Get the group information document.

The group information (GI) document allows programs to be put into groups such as serials, series, shows, or general themes and provide additional metadata for that group such as a description, links, and a logo. A program in the guide can be linked to its group using the "memberOf" field to allow clients to easily link programs together for a given Content Depot Program/Show in the EPG. GI will be published for all Content Depot programs that have the "publish metadata" option enabled. By using the group information, clients have the ability to access a single list of all metadata supported program titles, links, images, and descriptions. This information can be used to assist a station when setting up a schedule or it can be used in the end user metadata to provide additional information about the content such as displaying "other episodes from this program" or displaying the group, program, and program event images.

Currently all programs with "publish metadata" enabled will be included in the group information even if they are not active in the program guide. This may change in the future if the number of programs grows.

Note that while the location of the GI document isn't expected to change in the near future, as per the RadioDNS specification the authoritative link to the document is defined in the SI document with the mime value application/xml+gi.

The response will use standard HTTP cache-control headers to indicate when the document should be refreshed as well as an ETag to allow for lightweight change detection.