**As** a user of the API
**I want to** see the project-based semantic work package identifier and the user-facing identifier in the API
**so that** I can use the values if I like

**Acceptance criteria**

* the endpoints for getting work packages in the API v3 expose the Begin of the insertion`display_id`End of the insertion Begin of the deletion `user_facing_identifier`End of the deletion (based on the `Setting::WorkPackageIdentifier` either database ID or semantic ID), see <mention class="mention" data-id="73715" data-type="work_package" data-text="#73715">#73715</mention> for implementation details)


**Technical notes**

* We should not expose the `identifier` or `sequence_number` on the API

* In case the WorkPackageIdentifier Setting was set to `semantic` and then back to `classic`, and a work package is then moved from project A to project B, it&#39;s identifier will not be updated any more and still reference project A. Same for the sequence number.

* Begin of the insertion`display_id`End of the insertion Begin of the deletion `user_facing_identifier`End of the deletion should be a method of `WorkPackage` (and be called in the representer) since we also need it in views.


**Permissions and visibility considerations**

* Visibility of work packages does not change


**Translation considerations**

* No translations needed for the API


**Out of scope**

* <br>