It does, it’s done by
{{{content}}}
That is not embedding content in the sense the OP mentioned. Embedding content like a PDF would mean adding it as base64 data to the Markdown source.
From the Omnivore’s own support notes…
is probably
![[{{{fileAttachment}}}]]which is indeed doing transclusion of any fileattachment the Obsidian way
That is a very unwieldy and proprietary syntax specific to Omnivore and Obsidian. The MultiMarkdown syntax is plain and simple.
Welcome @thomasj3
Thanks for your comments.