It's been a while since I've done anything with the microformats2 markup on the blog. Most things are in place such as h-entry, h-card and h-feed.
Although it's currently only a proposed addition, I wanted to add u-audio to the
<audio> tags for the audio source of podcast episodes.
I use the PowerPress plugin to handle the episodes which add items via a shortcode so the u-audio class has to be inserted when loading the page.
Just like with making hashtags clickable links I needed to use the
add_filter hook on
preg_replace to add the u-audio class.