What is the meaning of # Optional in Google API documentation

Question

I am just beginning a study of the Google Calendar API. Here is a snippet which appears to be nested JSON syntax but I'd like to know more about the meaning of # Optional below (i.e. haven't found any discussion of this syntax in searching for JSON syntax):

"start": {
   "dateTime": "startTime",
   # Optional
   "timeZone": "America/Los_Angeles"
},
"end": {
   "dateTime": "endTime",
   # Optional
   "timeZone": "America/Los_Angeles"
},

Here is another snippet of this documentation where # is used differently:

"recurrence": [
   "RRULE:FREQ=WEEKLY;UNTIL=20110701T160000Z",
   # EXRULE, RDATE, EXDATE...
],

I am beginning to think this is just a comment in the documentation only - that is, it would not be considered comments in an actual JSON file per this:

Can comments be used in JSON?

Answer 1

I think it's just meant as a comment ... but it's not actual JSON syntax.