I have some PDFs which, when viewed in readers under Linux (tried atril from MATE and evince from GNOME), the ligatures (e.g. fi, fl) are missing, as can be seen from the example (it should be specifications):But when I view the same PDF in the built-in reader of Firefox (pdf.js) the ligatures are there; thus I know the PDF is not defective.This looks like either this bug a missing font, but how to discover which one? This is the list of fonts in the PDF file:I am using Debian unstable (jessie). What I have of fonts installed isii  ttf-bitstream-vera                    1.10-8                             all          The Bitstream Vera family of free TrueType fontsii  ttf-dejavu                            2.34-1                             all          transitional dummy packageii  ttf-dejavu-core                       2.34-1                             all          transitional dummy packageii  ttf-dejavu-extra                      2.34-1                             all          transitional dummy packageii  ttf-mscorefonts-installer             3.5                                all          Installer for Microsoft TrueType core fonts
Ligatures missing in some PDFs
fonts;pdf