BaseTemplate:renderAfterPortlet has only one known caller - Metrolook and was deprecated in 1.35. It will be removed in 1.37. Removing it will make our skin code easier to parse. BaseTemplate::getAfterPortlet duplicates functionality in Skin::getAfterPortlet so that should also be hard deprecated.
- Metrolook patched (courtesy patch) - see https://www.mediawiki.org/wiki/User:Jdlrobson/Skins_for_extension_developers#Q:_I_want_to_add_HTML_after_a_menu for how
- Monobook and Timeless are updated to not use BaseTemplate::getAfterPortlet
- BaseTemplate:renderAfterPortlet is hard deprecated
- BaseTemplate::getAfterPortlet is hard deprecated
- BaseTemplateAfterPortlet hook is hard deprecated
- Vector storybook is updated to refer to SkinAfterPortlet hook https://gerrit.wikimedia.org/g/mediawiki/skins/Vector/+/20d127a8dfb383226d650482c53ee8a66bd04291/stories/MenuPortal.stories.data.js#36