The “htx” parts in digital_publishing_workflow_tools with the earlier predecessor automated_digital_publishing comprise the early stages of a system that implements an abstract capability architecture standard (think POSIX) around the notion of small, independent tools/components supporting each other to perform higher-level operations. The goal is to build an Open Hypertext System for document aspects to follow later once the foundation is in place.
Integration can happen by adding a capability implementation or the whole system to an existing application or to call it as an external function/service. Another way would be to register an existing application or capability as the implementation for the system to invoke it, which requires the conformance of the capability implementation with the expected input/output as well as with the expected functional behavior. But there’s no need to integrate on the level of code execution: the system is designed to act on input automatically or user-driven, for which the input needs to either follow a scheme for semantic bootstrapping (think OSI model that establishes meaning with the help of wrapping “containers”), or, if it is from an external source, needs at least declare the identity of its format, so it can be imported/converted.
In practice, the system isn’t ready yet and most capabilities are still missing, so the approach is to simply bootstrap them. As the Doug@50/jrnl effort keeps changing, there’s no point any more in working with this journal in terms of content nor in interfacing with WordPress in terms of technology. The way to work together and integrate with the HTX system would be to just publish data under a libre-free license (preferably Creative Commons BY-SA 4.0) in an open format that adheres to a standard and making it retrievable via an open protocol. The HTX system will do the same for any party that wants and is able to cooperate/collaborate under these minimal requirements. Please actively notify me about cases where this has been done because a notification capability isn’t in place yet.