jetpack_fix_youtube_shortcode_display_filter() – Core changes to do_shortcode (https://core.trac.wordpress.org/changeset/34747) broke "improper" shortcodes with the format [shortcode=http://url.com].
jetpack_shortcode_get_youtube_id() – Required for class.media-extractor.php to match expected function naming convention.
wpcom_youtube_embed_crazy_url() – For bare URLs on their own line of the form http://www.youtube.com/v/9FhMMmqzbD8?fs=1&hl=en_US
youtube_link_callback() – Callback function for the regex that replaces YouTube URLs with YouTube embeds.
youtube_sanitize_url() – Normalizes a YouTube URL to include a v= parameter and a query string free of encoded ampersands.
Jetpack a2z