customization - Extracting data from Data paclet

In the $UserBasePacletsDirectory there are lots of paclets that have only Data as an element. These are loaded via the DataPaclets` functionality using the standard form:

DataPaclets`ImportData[
 pacletName<>"_"<>dataPart<>".wdx",
 DataPaclets`GetDataPacletResource[pacletName<>"_"<>dataPart, 
  dataSubpart<>".wdx"]
 ]

E.g.:

DataPaclets`ImportData[
 "ChemicalData_Index",

 DataPaclets`GetDataPacletResource[
  "ChemicalData_Index",
  "Properties.wdx"
  ]
 ]

This only works though when the .wdx file has the standard "Expression" part, e.g.:

DataPaclets`ImportData[
 "ChemicalData_Index",
 DataPaclets`GetDataPacletResource[

  "ChemicalData_Index",
  "Index.wdx"
  ]
 ]

this fails.

On the other hand for these indices we can pull stuff like:

DataPaclets`ImportData[
 "ChemicalData_Index",
 DataPaclets`GetDataPacletResource[

  "ChemicalData_Index",
  "Index.wdx"
  ],
 {"DataIndex", "Sources", "Data"}
 ]

Which will give us a long set of data specifying in what part we can find the actual data. For example we'll get something like "Part01" -> { ... } which seems to mean that the data for keys listed in that list can be found via:

DataPaclets`ImportData[
 "ChemicalData_Part01",
 DataPaclets`GetDataPacletResource[

  "ChemicalData_Part01",
  "Part01.wdx"
  ],
 {"DataTable", "Index"} (* Note that now we find the DataTable element *)
 ]

The problem is that the return from this is just a long list of really large ints and I have no idea what they mean and how to convert them to proper data.

I want to make my own Data paclet, but unfortunately I need to know how to export my data to make it work.

Does anyone know how to convert this? I really have no idea what it's supposed to be as the numbers range from around 440k to roughly 6 mil