FoundryVTT
You can import the data inside a FoundryVTT module. You need to download the module, unzip it and then import the module.json or system.json. S&D will then read the corresponding packs directory and create Data Sources from them.
Example
To try it out you can download the Classic Fantasy Compendium. Just download the module.zip, unzip and import the module.json in S&D.