To get linked id of Jira issue KR and Jira issue via JQL, use response id in 'linkedId' parameter in Get objective details API by. In get objective details API, use the parent objective id of respective Jira KR.
Response
Parent
Parameter
Type
Description
possible values
dateTimeFormat
String
dateFormat
keyResult
Object
keyResult
linkId
keyResult
type
Object
type
id
type
name
String
keyResult
progress
Object
progress
percent
progress
confidenceStatus
Object
confidenceStatus
id
confidenceStatus
name
String
progress
weightage
orderIndex
jql
This parameter is applicable only in case of Jira issue via JQL.