I've been looking into the development of custom models for CodeQL, as our internal codebases use a wide variety of bespoke libraries not currently modelled by CodeQL. For clarity, here is a link to the relevant documentation for custom models for Java and Kotlin codebases.

Unfortunately, the currently available documentation for custom models, regardless of langauge, is significantly lacking, to the point that development of models is challenging if not impossible without significant research. I was hoping to get some clarity on a number of issues, including but not limited to:

• Defining what value(s) are supported by different arguments. For example, sourceModel specifies a provenence parameter, but this parameter is not defined. Similarly, sinkModel specifies a kind variable, but I cannot find documentation on valid values for kind.
• While sourceModel and sinkModel have relatively intuitive uses, summaryModel and neutralModel are not defined. No intuition is provided as to when these models should be defined and what kind of impact having (or lacking) these models have on the success of a query.
• I cannot readily identify which models are natively supported within CodeQL and which would require new development. This information may be embedded within the code, but a cursory search did not yield results. Ideally, I would like this information documented somewhere clearly, as I would like to diff what open-source libraries are used within my codebase and the ones with existing support in CodeQL to identify which models would need to be contributed. Where appropriate, I would be happy to contribute these models back to the community.
• I see some documentation that suggests integration with VSCode would enable auto-generation of models or simplify the process. We do not use VSCode internally, so ideally this support would be provided as a standalone script or integrated within the CodeQL binary. Are there any plans to provide this functionality? If not, what is the ideal way of developing a significant amount of models?

Apologies for the excess of questions, but I figured organizing this into a single thread is better for visibility than creating multiple interrelated threads.