https://www.wondercms.com/
WonderCMS is the smallest flat file CMS for building websites and blogs, runs only on 5 files.
flat filesmallestcms
https://getgrav.org/
Grav is a Modern, Crazy Fast, Ridiculously Easy and Amazingly Powerful Flat-File CMS.
flat filegravmoderncms
https://github.com/imazen/folioxml
Folio Flat File to XML/HTML/Lucene conversion framework - imazen/folioxml
flat filegithubfolioxmlhtml
https://docs.oracle.com/en/middleware/idm/identity-governance-connectors/12.2.1.3/cftfl/configuring-application-connected-resource-using-flat-file-connector.html
Learn about configuring and managing flat files for a connected resource by using the connector.
for aapplicationconnectedresourceusing