Merge branch '268288-update-docs-for-live-preview-to-state-3rd-party-dependencies' into 'master'

Resolve "Update Docs for Live Preview to state 3rd Party Dependencies"

See merge request gitlab-org/gitlab!45588

doc/user/project/web_ide/index.md

@@ -5,7 +5,7 @@ info: "To determine the technical writer assigned to the Stage/Group associated
 type: reference, how-to
 ---
 
-# Web IDE
+# Web IDE **(CORE)**
 
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/4539) in [GitLab Ultimate](https://about.gitlab.com/pricing/) 10.4.
 > - [Moved](https://gitlab.com/gitlab-org/gitlab-foss/-/issues/44157) to GitLab Core in 10.7.
@@ -244,6 +244,8 @@ quickly share your project with others.
 
 ### Enabling Live Preview
 
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/268288) in GitLab 12.9, third-party assets and libraries required for Live Preview are hosted at `https://sandbox-prod.gitlab-static.net` when it is enabled. However, some libraries are still served from other third-party services which may or may not be desirable in your environment.
+
 The Live Preview feature needs to be enabled in the GitLab instances
 admin settings. Live Preview is enabled for all projects on
 GitLab.com