cmake project data structure type (public lib)?

This is rather a question.
There are a lot of legacy projects that use Visual Studio or MakeFile or whatever. I myself have an old legacy project that I’d be very glad to migrate to CMake using some automation.
The thing is, it would be easier for people with similar intentions to use an internal CMake Project structure as a reference. For instance, one would fill it with values acquired from .proj and .sln files and then use it to populate a set of CMakeLists.txt.

It is easier to do those things when you have a well structured domain data that can be used.
Are there any libraries that provide any Public API for internal project structure? If not, would it be reasonable to make such a library within an official CMake package?

PS: I am aware of existing projects on GitHub, but they are not suited for my needs since they don’t handle many cases. But a data reference would simplify things dramatically.

Maybe you’d be interested in using a conversion tool such as

I’ve never used it myself, so I can’t tell how well it works.

I have mentioned in the question that I’m aware of existing solutions and they are not fit for my purposes - they do not handle many corner cases within my project. Also I’d like to customise the output for the generated files.
Also the project is not maintained well. I don’t want to spend my time on figuring out its internals and ending up with a diverged fork.
On the other side, having a concise project data types library would enable many userrs to customize the output and also intoduce addons for converting from other systems.

This question is about existing data structures that might be reused. There might be none, you know.