Document how posts are prepared for export to Apple News, including supported and unsupported blocks #1251
Description
It is not clear from the WordPress plugin directory page nor this repository's README how this plugin processes the content of a post to prepare it for exporting to Apple News. The debug functionality shows you the JSON that will be sent to Apple News, but there is no explanation of how that JSON is generated from the post content in the first place.
I was very confused why certain blocks were being excluded from the JSON, only to discover, by spending time looking through the plugin code, that Custom HTML blocks are skipped completely by the plugin and Shortcode blocks aren't rendered—in fact, the plugin skips any block that does not match a component in includes/apple-exporter/components. This does not seem to be documented anywhere, but it seems very important to point out.
Could we add a section to the README or the plugin page that lists the supported blocks?