ACTIVITIES, ORGANIZATIONS fields type and value

endpoint
field
#1

Hi every one.
I am a new here.

I’m trying find types to next fields, but can’t found nothing .
End-point:
https://api.pipedrive.com/v1/activities
Fields:
“reference_type”,
“reference_id”,
“gcal_event_id”,
“google_calendar_id”,
“google_calendar_etag”,
“source_timezone”,
“rec_rule”,
“rec_rule_extension”,
“rec_master_activity_id”,
“series”

End-point:
https://api.pipedrive.com/v1/organizations
Fields:
“category_id”,
“country_code”,

Which type have this fields ?
How I can set value for this fields ?

#2

From the looks of your results, none of these are editable Fields (or at least not directly editable).
This article might give you some advice on you can edit the values of fields (custom).