1 files changed, 5 insertions, 84 deletions
diff --git a/doc/development/activitypub/actors/topic.md b/doc/development/activitypub/actors/topic.md
index f99a6e0569a..2cac837791f 100644
--- a/doc/development/activitypub/actors/topic.md
+++ b/doc/development/activitypub/actors/topic.md
@@ -2,90 +2,11 @@
 stage: Create
 group: Source Code
 info: "To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/product/ux/technical-writing/#assignments"
+remove_date: '2024-01-22'
+redirect_to: 'index.md'
 ---
 
-# Activities for topic actor **(EXPERIMENT)**
+# Activities for topic actor (removed)
 
-> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/127023) in GitLab 16.5 [with two flags](../../../administration/feature_flags.md) named `activity_pub` and `activity_pub_project`. Disabled by default. This feature is an [Experiment](../../../policy/experiment-beta-support.md).
-
-FLAG:
-On self-managed GitLab, by default this feature is not available. To make it available,
-an administrator can [enable the feature flags](../../../administration/feature_flags.md)
-named `activity_pub` and `activity_pub_project`.
-On GitLab.com, this feature is not available.
-The feature is not ready for production use.
-
-This feature requires two feature flags:
-
-- `activity_pub`: Enables or disables all ActivityPub-related features.
-- `activity_pub_project`: Enables and disable ActivityPub features specific to
-  projects. Requires the `activity_pub` flag to also be enabled.
-
-## Profile
-
-```javascript
-{
-  "@context": "https://www.w3.org/ns/activitystreams",
-  "id": TOPIC_URL,
-  "type": "Group",
-  "name": TOPIC_NAME,
-  "url": TOPIC_URL,
-  "summary": TOPIC_DESCRIPTION,
-  "outbox": TOPIC_OUTBOX_URL,
-  "inbox": null,
-}
-```
-
-## Outbox
-
-Like the release actor, the topic specification is not complex. It generates an
-activity only when a new project has been added to the given topic.
-
-```javascript
-{
-  "id": TOPIC_OUTBOX_URL#event_id,
-  "type": "Add",
-  "to": [
-    "https://www.w3.org/ns/activitystreams#Public"
-  ],
-  "actor": {
-    "id": PROJECT_URL,
-    "type": "Application",
-    "name": PROJECT_NAME,
-    "url": PROJECT_URL,
-  },
-  "object": {
-    "id": TOPIC_URL,
-    "type": "Group",
-    "name": TOPIC_NAME,
-    "url": TOPIC_URL,
-    },
-  },
-}
-```
-
-## Possible difficulties
-
-There is hidden complexity here.
-
-The simpler way to build this endpoint is to take the projects associated
-to a topic, and sort them by descending creation date. However,
-if we do that, discrepancies will occur when implementing the
-activity push part of the standard.
-
-Adding the project to a topic is not made at project creation time. It's
-made when a project's topics are _edited_. That action can happen a very long time
-after the project creation date. In that case, a push activity is
-created and sent to federated instances when adding the topic to the
-project. However, the list in the outbox endpoint that sorts projects by descending
-creation date doesn't show the project, because it was created long ago.
-
-No special logic happens when a topic is added to a project, except:
-
-- Cleaning up the topic list.
-- Creating the topic in database, if it doesn't exist yet.
-
-No event is generated. We should add such an event so the activity
-push create an event, ideally in `Projects::UpdateService`. Then, the outbox endpoint
-can list those events to be sure to match what was sent. When doing that, we should
-verify that it doesn't affect other pages or endpoints dealing with events.
+This feature was documented [before it was implemented](https://gitlab.com/gitlab-org/gitlab/-/issues/426372).
+See [Implement an ActivityPub actor](index.md) instead.