Add OutputPipelineStages from extensions

Adds an experimental configuration to allow extensions to define
OutputPipelineStages to include in the DefaultOutputPipeline.

There are a lot of open questions about this api, like ordering of
execution, but adding it @experimental will help surface the
requirements.

Bug: T370541
Needed-By: I6dc92af0611c680b6e55605a7c9ff8a3fc1dfa26
Change-Id: I64baea40a1687c7a06fbcda9efe9f9a159b0ae8d

1 files changed, 11 insertions, 0 deletions

diff --git a/includes/MainConfigSchema.php b/includes/MainConfigSchema.php
index 23566e278dd5..3ee9f64b6edf 100644
--- a/includes/MainConfigSchema.php
+++ b/includes/MainConfigSchema.php
@@ -12902,6 +12902,17 @@ class MainConfigSchema {
 		'default' => false,
 		'type' => 'boolean',
 	];
+
+	/**
+	 * OutputPipelineStages to add to the DefaultOutputPipeline.
+	 *
+	 * @unstable EXPERIMENTAL
+	 * @since 1.43
+	 */
+	public const OutputPipelineStages = [
+		'default' => [],
+		'type' => 'map',
+	];
 	// endregion -- End Miscellaneous
 
 }