I'm interested to download pdf files from a website but httrack wont recognize
them.
I Explored webpage source and recognized that the pdf is embedded 

embed id="plugin" type="application/x-google-chrome-pdf"
src=https://cdn.datasheetspdf.com/pdf-down/C/D/4/CD4066B-etcTI.pdf

I guess that Httrack wont recognized embedded links correctly