title: Extract vectorized data from a pdf with non-embedded fonts
body: <p>My question is about how PDF viewers handle fonts used in a PDF that are not embedded.</p>
  <p>I'm using software (pdfjs-dist) to generate thumbnails from PDF's and noticed that text is often missing in the resulting image.
  Upon further inspection it turns out that fonts are missing on the OS (which is a node docker container (linux)).</p>
  <p>Now, I have heard that it's possible to always generate a render from a PDF, using some sort of layer in the PDF that contains vectorized data which you can view,
  <em>even when the fonts are not embedded in the PDF nor available in the operating system</em>.</p>
  <p>Has anyone heard of this mechanism that can point me to its technical name?</p>