Allows you to check the document for fonts that are embedded but can be emulated for viewing by Adobe Acrobat.
Embedding fonts in a PDF document means that every character of this font is copied and stored in the PDF document. This is useful if you create PDF documents to be displayed on different systems and to be printed on different devices: these are often systems that do not contain exactly the same fonts. Also, if a font has been embedded, you can still edit the text in the PDF file that uses the font in question, even though the font has not been installed on your computer.
Some fonts can be emulated by Adobe Acrobat for on-screen viewing. This means that if the font is unavailable on your system Adobe Acrobat can re-create the font visually, even though it has not been embedded.
If you are certain the document only needs to be viewed on-screen, and will not be printed, fonts that can be emulated do not need to be embedded.
You can unembed these fonts. This will decrease the PDF file size.