Merge branch 'docs-update-ci-shared-minutes' into 'master'

Expand the details of shared runner minutes

See merge request gitlab-org/gitlab!66351

doc/subscriptions/gitlab_com/index.md

@@ -274,13 +274,31 @@ If you add a member to a group by using the [share a group with another group](.
 
 CI pipeline minutes are the execution time for your [pipelines](../../ci/pipelines/index.md)
 on GitLab shared runners. Each [GitLab SaaS tier](https://about.gitlab.com/pricing/)
-includes a monthly quota of CI pipeline minutes for private and public projects:
-
-| Plan     | Private projects | Public projects |
-|----------|------------------|-----------------|
-| Free     | 400              | 50,000          |
-| Premium  | 10,000           | 1,250,000       |
-| Ultimate | 50,000           | 6,250,000       |
+includes a monthly quota of CI pipeline minutes for private and public projects in
+the namespace:
+
+| Plan     | CI pipeline minutes |
+|----------|---------------------|
+| Free     | 400                 |
+| Premium  | 10,000              |
+| Ultimate | 50,000              |
+
+The consumption rate for CI pipeline minutes is based on the visibility of the projects:
+
+- Private projects in the namespace consume pipeline minutes at a rate of 1 CI pipeline minute
+  per 1 minute of execution time on GitLab shared runners.
+- Public projects in:
+  - Namespaces [created on or after 2021-07-17](https://gitlab.com/gitlab-org/gitlab/-/issues/332708)
+    consume pipeline minutes at a slower rate, 1 CI pipeline minute per 125 minutes
+    of execution time on GitLab shared runners. The per-minute rate for public projects
+    is 0.008 CI pipeline minutes per 1 minute of execution time on GitLab shared runners.
+  - Namespaces created before 2021-07-17 do not consume CI pipeline minutes.
+
+| Plan     | CI pipeline minutes | Maximum **private** project execution time (all namespaces) | Maximum **public** project execution time (namespaces created 2021-07-17 and later) |
+|----------|---------------------|-------------------------------------------------------------|-------------------------------------------------------------------------------------|
+| Free     | 400                 | 400 minutes                                                 | 50,000 minutes                                                                      |
+| Premium  | 10,000              | 10,000 minutes                                              | 1,250,000 minutes                                                                   |
+| Ultimate | 50,000              | 50,000 minutes                                              | 6,250,000 minutes                                                                   |
 
 Quotas apply to: