What are the possible values for the expand parameter in Confluence Server REST API?

Hello Community,

the Confluence Server REST API documentation for /get/content/ (e. g. https://docs.atlassian.com/ConfluenceServer/rest/8.5.7/#api/content-getContent) defines what are the default values of the “expand” parameter.

Okay, but where can I find the complete set of possible “expand” values, (with explanation of each value)?

If the valid value set for “expand” is specific for /get/content, where are the valid values specified?

Thank you.