Hidden spaces are not listed by the GET /wikis/{wikiName}/spaces REST API

Not sure it is a bug or a feature.

On a default install, you can notice that the Help.Applications.Movies.Code space is not returned by http://localhost:8080/xwiki/rest/wikis/xwiki/spaces

IMHO, it should return the hidden spaces. That might be a breaking change so introducing a "hidden" parameter allowing the REST clients to opt in for hidden spaces would be nice.

If there is already such a parameter, it might be worth documenting at https://www.xwiki.org/xwiki/bin/view/Documentation/UserGuide/Features/XWikiRESTfulAPI#HSpaceresources