Firefox 80 Ships With the Option to Make Its PDF Viewer Your System Default
Firefox 80 lets its built-in PDF reader take over as the OS default, alongside a blocklist refresh and WebRTC congestion-control gains.
Mozilla pushed out Firefox 80 today, and the headline change is a small one that a lot of people have quietly wanted for a while: you can now set Firefox’s built-in PDF viewer (the one that’s been rendering PDFs inline in tabs for years) as your operating system’s default handler for PDF files. Double-click a PDF on your desktop, and instead of launching Adobe Reader or Preview or whatever else claimed the file association at some point, it opens straight into a Firefox tab.
This has technically been possible to hack around before, but Firefox is now making the option official and easy to find in the settings. It’s the kind of feature that sounds minor until you realize how many people still have a bloated PDF reader installed purely because it grabbed the default file association during setup and never let go. Firefox’s viewer is fast, it’s already open if you have the browser running, and it doesn’t nag you about premium upgrades. For anyone who mostly just wants to read PDFs rather than annotate or sign them, this is a reasonable replacement for a dedicated app.
Cleanup under the hood
Alongside the PDF news, Mozilla refreshed the add-ons blocklist in this release. Firefox maintains a list of extensions that are blocked outright for security or performance reasons, and periodically that list needs pruning and updating as new problem extensions get flagged and old entries become irrelevant. The practical effect for most users is invisible — you just get a browser that’s a little less likely to be dragged down by a rogue extension nobody remembers installing.
WebRTC gets steadier under bad connections
The more technically interesting change is on the WebRTC side. Firefox 80 adds support for Transport-cc (transport-wide congestion control), which is a mechanism used in video calling to help the browser figure out, packet by packet, how much bandwidth is actually available right now rather than reacting only after things fall apart. If you’ve been on a Firefox-based video call where your connection wasn’t great and the video just kept freezing or the audio cut out, congestion control improvements like this are aimed directly at that problem. It won’t fix a genuinely bad connection, but it should mean calls degrade more gracefully — dropping video quality smoothly instead of stuttering to a halt — which matters a lot given how many people are relying on browser-based video calls for work and school right now.
None of these are flashy, headline-grabbing features on their own, but together they’re a good snapshot of what a mature browser release looks like in 2020: a genuinely useful default-app change, quiet security housekeeping, and real-world reliability work on the video calling stack that underpins a huge chunk of daily life at the moment. If you’ve been putting off Firefox updates, this one’s worth grabbing — especially if you’ve ever wished you could just kill your third-party PDF reader for good.