The format of vulkaninfo‘s JSON output is designed to be used as input to the LunarG Device Simulation (DevSim) layer. When changes are made to vulkaninfo’s JSON output, the formatting should be validated against DevSim's JSON schema, to ensure the text is correctly formatted.
The DevSim JSON schema specifies exactly how its JSON input data must be structured. The schema may be found at https://schema.khronos.org/vulkan/devsim_1_0_0.json
vulkaninfo --jsonand save to a file.
Each of these tools seem to have their own quirks and/or holes in coverage. I recommend using all of them, ensuring they all report that the data successfully validates against the schema.
If you have suggestions for better tools (e.g.: an official reference validator, an automatable tool to integrate with continuous integration) please create an issue to recommend it.