https://www.fontoxml.com/blog/migrating-from-xopus-to-fonto-editor/
Migrating from Xopus to Fonto Editor - Edit XML in the browser
Aug 18, 2021 - How to migrate from Xopus to Fonto Editor? What are the necessary steps, and points of attention, when migrating from Xopus to Fonto Editor?
fonto editorin themigrating
https://www.fontoxml.com/
Structured content authoring made easy - Fonto XML Editor
Fonto: the online XML editor, designed for people with no knowledge of XML or any other technology that comes with structured content authoring.
content authoring made easystructuredfontoxmleditor