Industry seems to push LTI as the next big standard for integrating online and mobile learning platforms and services. If I look at the IMS LTI compliance web page, I see mostly services that are dealing with Open Badges among LTI-compliant open-source tools. And yes, there are few old and stable platforms (such as Moodle or TAOtesting) that have managed to ensure LTI compliance. What I am looking for is a lightweight (and responsive) open-source learning content authoring tool to build interactive (light QTI-style) companion content for digital textbooks.
(Thread started long time ago here - and not by me - https://www.researchgate.net/post/Do-you-happen-to-know-any-open-source-LTI-compliant-learning-content-authoring-tools but no useful outcome)