'Planned Start Date' and 'Planned End Date' API
Accepted answer
That display data is calculated based on plan snapshots. The planning component does not expose an official API I would be aware of.
Comments
Is there any other way to fetch this Attribute value.
As far as I know it is not an attribute value. There is no attribute that represents this, It is also not listed as an attribute value that can be displayed and accessed in queries.
As far as I can tell it is a not attribute based editor presentation of the kind Planned Time with the ID com.ibm.team.apt.presentation.plannedtime. I am not aware of a way to get the information for it.
I think,it is possible by using Rest API.