- Specifies a globally unique ID for a page. This guid will be used,
- rather than the page url, to identify the page in RSS and Atom feeds.
+ Specifies a globally unique ID for a page. This guid should be a URI
+ (in particular, it can be `urn:uuid:` followed by a UUID, as per
+ [[!rfc 4122]]), and it will be used to identify the page's entry in RSS
+ and Atom feeds. If not given, the default is to use the page's URL as its
+ guid.