No.

The JSON is data only, and if you include a comment, then it will be data too.

You could have a designated data element called "_comment" (or something) that should be ignored by apps that use the JSON data.

You would probably be better having the comment in the processes that generates/receives the JSON, as they are supposed to know what the JSON data will be in advance, or at least the structure of it.

But if you decided to:

{    "_comment": "comment text goes here...",    "glossary": {       "title": "example glossary",       "GlossDiv": {          "title": "S",          "GlossList": {             "GlossEntry": {                "ID": "SGML",                "SortAs": "SGML",                "GlossTerm": "Standard Generalized Markup Language",                "Acronym": "SGML",                "Abbrev": "ISO 8879:1986",                "GlossDef": {                   "para": "A meta-markup language, used to create markup languages such as DocBook.",                   "GlossSeeAlso": ["GML", "XML"]                },                "GlossSee": "markup"             }          }       }    } }