Open in Sumatra PDF and DJVU Reader by Andy Portmen

This extension uses the open-source "Sumatra PDF" to handle your PDF and DJVU files. The extension offers integration. There are two methods to send a PDF or DJVU link to the Sumatra PDF. You can either use the right-click context menu item for PDF links or let the browser open the PDF file in a browser tab and then use the browser action button to send the PDF file to Sumatra PDF. Note that since Sumatra PDF does not support HTTP and HTTPS protocols, this extension first downloads the PDF files to your default download directory and then sends the actual local path to the Sumatra PDF.

Also note that since there is an interaction with a native application, this extension needs a helper module. This module is written in JavaScript and uses the official NodeJS executable. The instruction to install the native client will be displayed on the first usage.

Notes:
This extension uses a native helper to interact with Sumatra PDF
There is no server-side interaction whatsoever other than downloading the PDF file to the default download directory.
The native helper uses the official NodeJS executable.

Legal:
This extension only helps to ease the Sumatra PDF integration. There is no claim that this extension does the PDF rendering or is developed by Sumatra PDF team.