My suggestion for PDF reader
PDF.js - https://github.com/mozilla/pdf.js
https://addons.mozilla.org/En-us/firefox/addon/pdfjs
Because it works with free software browser Firefox.
Regards.
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Minha sugestão para leitor de PDF
Sugiro PDF.js https://github.com/mozilla/pdf.js pois funciona com navegador Firefox.
https://addons.mozilla.org/En-us/firefox/addon/pdfjs
Saudações livres.