Jetpack_Keyring_Service_Helper::add_sharing_menu() – We need a `sharing` submenu page to be able to connect and disconnect services.
Jetpack_Keyring_Service_Helper::api_url() – Gets a URL to the public-api actions. Works like WP’s admin_url
Jetpack_Keyring_Service_Helper::connect_url() – Filters the API URL used to interact with WordPress.com.
Jetpack_Lazy_Images::flatten_kses_hair_data() – Allows plugins and themes to modify the placeholder image.
Jetpack_Recipes::add_recipes_kses_rules() – Add Schema-specific attributes to our allowed tags in wp_kses, so we can have better Schema.org compliance.
User_Agent_Info::is_kindle_fire() – Detects if the current browser is the Kindle Fire Native browser.
User_Agent_Info::is_kindle_touch() – Detects if the current browser is the Kindle Touch Native browser
WPCom_Markdown::maybe_remove_kses() – Remove KSES if it’s there. Store the result to manually invoke later if needed.
WPCom_Markdown::wp_kses_allowed_html() – Some tags are allowed to have a ‘markdown’ attribute, allowing them to contain Markdown.