What is creating certain fields?

[Keith Dopson]

My default query produces this:

|  {
        "id":"44419",
        "date":["11/13/17 13:18"],
        "url":["http://www.someurl.com";],
        "title":["some title"],
        "content":["some indexed content..........."],
        "date_str":["11/13/17 13:18"],
        "url_str":["http://www.someurl.com";],
        "title_str":["some title"],
        "_version_":1594211356390719488,
        "content_str":["some indexed content.........."]
},


In my managed_schema file, I only have five populated fields,

   <field name="id" type="string" indexed="true" stored="true" required="true" 
multiValued="false" />

   <field name="date"    type="text_general" indexed="false" stored="true"/>
   <field name="url"     type="text_general" indexed="false" stored="true"/>
   <field name="title"   type="text_general" indexed="true"  stored="true"/>
   <field name="content" type="text_general" indexed="true"  stored="true"/>

While other fields are declared, none of them are populated by my "post" 
command.

My question is "Where are the xxxxx_str fields coming from?
I.e., what is producing the
|
||"date_str":["...
"url_str":["...
"title_str":["...
"content_str":["...|

entries?

Thanks in advance.
|