Fires functions hooked onto `after_setup_theme` by the theme for the purpose of the REST API. The REST API does not load the theme when processing requests. To enable theme-based functionality, the API will load the ‘/functions.php’, ‘/inc/jetpack.compat.php’, ‘/inc/jetpack.php’, ‘/includes/jetpack.compat.php files of the theme (parent and child) and copy functions hooked onto ‘after_setup_theme’ within those files.
Changelog
- Introduced in Jetpack 3.2.0
Jetpack Developer Resources 