Starting in Blender 4.2, extensions are the new way of doing add-ons and themes. Legacy add-ons are considered deprecated but continue to be supported. See Here: https://docs.blender.org/manual/en/4.2/advanced/extensions/addons.html#legacy-vs-extension-add-ons If you are on a version of Blender older than 4.2, the legacy add-on is the one to download. Installation Instructions: https://cgmeerkat.readthedocs.io/en/latest/addons_installation.html Origin Wrangler is built as an extension and a legacy add-on in order to support more Blender versions. Origin Wrangler’s features do not differ between its legacy and extension variants.