Deprecation notice for merged_by field

data/deprecations/14-7-deprecate-merged_by-api-field.yml

+# This is a template for a feature deprecation
+# A deprecation typically occurs when a feature or capability is planned to be removed in a future release.
+# Deprecations should be announced at least two releases prior to removal.  Any breaking changes should only be done in major releases.
+#
+# Below is an example of what a single entry should look like, it's required attributes,
+# and what types we expect those attribute values to be.
+#
+# For more information please refer to the handbook documentation here:
+# https://about.gitlab.com/handbook/marketing/blog/release-posts/#deprecations
+#
+# Please delete this line and above before submitting your merge request.
+
+- name: "merged_by API field" # The name of the feature to be deprecated
+  announcement_milestone: "14.7" # The milestone when this feature was first announced as deprecated.
+  announcement_date: "2022-01-22" # The date of the milestone release when this feature was first announced as deprecated. This should almost always be the 22nd of a month (YYYY-MM-22), unless you did an out of band blog post.
+  removal_milestone: "15.0" # The milestone when this feature is planned to be removed
+  breaking_change: false # If this deprecation is a breaking change, set this value to true
+  body: | # Do not modify this line, instead modify the lines below.
+    The `merged_by` field in the [merge request API](https://docs.gitlab.com/ee/api/merge_requests.html#list-merge-requests) is being deprecated and will be removed in GitLab 15.0. This field is being replaced with the `merge_user` field (already present in GraphQL) which more correctly identifies who merged a merge request when performing actions (merge when pipeline succeeds, add to merge train) other than a simple merge.
+# The following items are not published on the docs page, but may be used in the future.
+  stage: create # (optional - may be required in the future) String value of the stage that the feature was created in. e.g., Growth
+  tiers: # (optional - may be required in the future) An array of tiers that the feature is available in currently.  e.g., [Free, Silver, Gold, Core, Premium, Ultimate]
+  issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/350534 # (optional) This is a link to the deprecation issue in GitLab
+  documentation_url: # (optional) This is a link to the current documentation page
+  image_url: # (optional) This is a link to a thumbnail image depicting the feature
+  video_url: # (optional) Use the youtube thumbnail URL with the structure of https://img.youtube.com/vi/UNIQUEID/hqdefault.jpg

doc/update/deprecations.md

@@ -504,3 +504,9 @@ Planned removal milestone: 15.0 (2022-05-22)
 Tracing in GitLab is an integration with Jaeger, an open-source end-to-end distributed tracing system. GitLab users can navigate to their Jaeger instance to gain insight into the performance of a deployed application, tracking each function or microservice that handles a given request. Tracing in GitLab is deprecated in GitLab 14.7, and scheduled for removal in 15.0. To track work on a possible replacement, see the issue for [Opstrace integration with GitLab](https://gitlab.com/groups/gitlab-org/-/epics/6976).
 
 Planned removal milestone: 15.0 (2022-05-22)
+
+### merged_by API field
+
+The `merged_by` field in the [merge request API](https://docs.gitlab.com/ee/api/merge_requests.html#list-merge-requests) is being deprecated and will be removed in GitLab 15.0. This field is being replaced with the `merge_user` field (already present in GraphQL) which more correctly identifies who merged a merge request when performing actions (merge when pipeline succeeds, add to merge train) other than a simple merge.
+
+Planned removal milestone: 15.0 ()