I couldn't find the following api call : /rest/graphql/1/ in the documentation

Hussein Dbouk

Hi there , in my cloud instance https://azizpremium2.atlassian.net/ I have a ticket that has Insight Fields which are custom fields, I searched in the network of the inspect in the google chrome and I found that /rest/graphql/1/ is the api that gets the information of these insight fields 
where as the /rest/api/2/issue/$issueKey?expand=renderedFields,names,schema,operations,changelog&fields=*all&updateHistory=true&properties=*all didnt reveal the information about these custom fields 
I need you please to help me get the body (payload) of the  /rest/graphql/1/ api call

Hussein Dbouk

{

"query":

"query fieldConfigurationQuery(\$issueKey: String) { issue(issueIdOrKey: \$issueKey, latestVersion: true, screen: \"view\") { fields { key schema { type custom customId system renderer } autoCompleteUrl allowedValues operations required editable title } } }",

"variables": {"issueKey": "$issueKeyParam"}

 }