This is currently being re-computed and refetched every few minutes in the startup module without caching. Overall, the data does not appear to be critical to page views or otherwise needed before we can fetch modules on any page on any wiki.
Rather, it should be bundled with the ext.wikiEditor module that needs it, which already bundles the consumer of this data (jquery.wikiEditor.toolbar.config.js).
Slows down computation of the startup module on cache miss.
Increases bandwidth cost on all pages in the path towards loading interactive features, which delays VisualEditor and Popups (a little bit).