What does it show?

Description of PDF fonts can be found in the PDF.

How to interpret the result?
Shows the list of non-embedded fonts.

PDF: Check embedded letters.

What does the warning mean?
Checking the fonts of PDF
If the font description is not in the PDF, foreign characters may be substituted for the original text when printed.
Non-embedded font in the PDF
Unfortunately, the problem can be corrected only on a machine in which the missing font type is available.
How the problem could be resolved?