Can anyone explain the major features of a VDPROJ file?

Question

I'm sure there must be some documentation on MSDN somewhere, but I couldn't find it. It looks like some subset/variation of JSON. Really, this question grew out of something that has always bugged me: what do all the 8:s and 3:s mean? Is this some a version number of some kind? Maybe a typing scheme? Every VDPROJ excerpt I've ever seen is filled with these "eight-colon" and "three-colon" prefixes, but this is not the sort of question search engines are really good for.

"DeployProject"
{
"VSVersion" = "3:800"
"ProjectType" = "8:{978C614F-708E-4E1A-B201-565925725DBA}"
"IsWebType" = "8:FALSE"
"ProjectName" = "8:ProjectNameRedacted"
"LanguageId" = "3:1033"
"CodePage" = "3:1252"
"UILanguageId" = "3:1033"
"SccProjectName" = "8:"
"SccLocalPath" = "8:"
"SccAuxPath" = "8:"
"SccProvider" = "8:"
    "Hierarchy"
    {
        "Entry"
        {
        "MsmKey" = "8:_02F97BB7BD104F1AAA1C97C854D5DC99"
        "OwnerKey" = "8:_UNDEFINED"
        "MsmSig" = "8:_UNDEFINED"
        }
...

If anyone just wants to berate my pitiful Google-fu, that's fine too.

Answer 1

As @R. Matveev pointed out, the prefix numbers likely indicate the type of data stored in the property. This would be useful when deserializing the file into an object structure.

I doubt the source code which Visual Studio used to read/write the files was ever made open source, so it's no wonder that web searches returned nothing.

The best I could find was this page on OLE Automation data types, which may not have been the actual constants, but the data types seem to match the values in the *.vdproj file.

2.2.7 VARIANT Type Constants

typedef  enum tagVARENUM
 {
   VT_EMPTY = 0x0000,
   VT_NULL = 0x0001,
   VT_I2 = 0x0002,
   VT_I4 = 0x0003, // 4-byte signed integer
   VT_R4 = 0x0004,
   VT_R8 = 0x0005,
   VT_CY = 0x0006,
   VT_DATE = 0x0007,
   VT_BSTR = 0x0008, // BSTR (string data)
   VT_DISPATCH = 0x0009,
   VT_ERROR = 0x000A,
   VT_BOOL = 0x000B, // Boolean value
   VT_VARIANT = 0x000C,
   VT_UNKNOWN = 0x000D
   ...
 } VARENUM;