I was just told by the Chat support person that in order to view/edit source code for an email built using the Drag and Drop (beta) editor you need to manually enter a different URL for the content.
The original content link:
https://app.maropost.com/accounts/693/contents/drag_and_drop_beta/6243615
Then in order to view the source code for the above email, you must use this URL format here: https://app.maropost.com/accounts/693/contents/6243615/edit
And then click the "Source" button in the toolbar menu.
(So this is basically a rendering of your content viewed in an older version of the content builder.)
So for any content built using Drag and Drop (beta) editor, you need to, apparently, bookmark that second URL in your browser (which seems ridiculous) and swap out the content ID in it for the actual email that you want source code for.
Can't a "view source code" button/option just be added to the Drag and Drop (beta) UI?