For those that enjoy a bit of historical perspective, it is interesting to note that similar schema repositories existed also for XML (for both DTD and XML Schema). They were, however, all behind paywalls or registration forms.<p>It is impressive to see how much and how quickly the world has switched to "open-first" when it comes to schemas, documentation and software in general.<p>Examples:<p>* BizTalk (by Microsoft) <a href="https://web.archive.org/web/20000301195519/http://www.biztalk.org/Library/library.asp" rel="nofollow">https://web.archive.org/web/20000301195519/http://www.biztal...</a><p>* <a href="https://web.archive.org/web/20000511095737/http://www.openapplications.org/xml/loadform.htm" rel="nofollow">https://web.archive.org/web/20000511095737/http://www.openap...</a><p>Bonus: A review of XML schema repositories: <a href="https://www.xmltwig.org/article/bw/bw_04-schema_repositories.html" rel="nofollow">https://www.xmltwig.org/article/bw/bw_04-schema_repositories...</a>