This ticket tracks a first version of making Firefox the default PDF handler when it is set as default on Windows. We want to:

1. Have "Make Firefox default" set Firefox as the default PDF handler for new profiles, providing that another browser is the current default PDF handler.

   Tracked by Bug 1761504.

2. Change the presence of PDF files in Windows when Firefox is the default PDF handler.

   We want the display icon to be the Windows default PDF icon and for the file type to be displayed as "Firefox PDF document" (it is currently "Firefox HTML document"). Tracked by Bug 1761389.

romain: our existing work only targets Windows 10: https://bugzilla.mozilla.org/show_bug.cgi?id=1743914. It's probably possible to tackle Windows 7, but the development burden is a good deal higher. I'm going to assume everything is Windows 10 (and above) and then we'll investigate support for Windows 7 next week; we might need to push that back to Fx 101. NI just for your context.

That makes sense, most of our Windows acquisition comes from Win10 (which I assume also means Win11).

No need to be MoCo-only: all the parts have landed and are not MoCo-only.

Testing

There are 3 functional parts to test:

1. when Firefox is the default PDF handler, we should have a pretty new icon
2. when Firefox is the default PDF handler, we should say "Firefox PDF Document" (rather than the older "Firefox HTML Document")
3. when Gecko preference browser.shell.setDefaultPDFHandler=true, then setting Firefox as the default browser sets Firefox as the default PDF handler when the existing handler is a recognized browser (i.e., is not Acrobat Reader). This is regardless of entry point (i.e., about:preferences, about:welcome, or startup modal -- all set Firefox as the default PDF handler).

There are a few different scenarios to verify; I will only walk through one, but I will describe the others I would like QA to verify. This testing can be done with Firefox Beta 100.0b1 when it is released.

Throughout: The easiest way to set the default PDF handler and to ensure icons are refreshed is to, within Windows Explorer, use Open With > Choose other app ... and check "Always use this app to open .pdf files".

Note: everything here is Windows 10+; more on Windows 7 below.

Verify functionality

1. Install Firefox with these changes landed. I am using this Win64 build from autoland.
2. I will install without elevation to C:\Users\nalexander\AppData\Local\Firefox Nightly\.
3. Ensure that a browser is the default PDF handler -- for example, Microsoft Edge. Verify that file description and icon in Windows Explorer are not specific to Firefox.
4. Within Firefox, set browser.shell.setDefaultPDFHandler=false.
5. In about:preferences, make Firefox default.
6. In Windows Explorer, verify that Firefox is not the default PDF handler. (The feature is not enabled, so even though a browser is the existing default, we should leave the PDF default alone.)
7. Within Firefox, set browser.shell.setDefaultPDFHandler=true.
8. In about:preferences, make Firefox default.
9. In Windows Explorer, verify that Firefox is the default PDF handler. (The feature is enabled and another browser is the existing default, so we should take the PDF default.)
10. Verify that text description of a PDF file is "Firefox PDF Document" and the icon is the new red PDF icon, like the attached images.
11. Ensure that a non-browser is the default PDF handler -- for example, Adobe Acrobat Reader. Verify that file description and icon in Windows Explorer are not specific to Firefox.
12. Set another browser to the default browser, so that within Firefox about:preferences, you can make Firefox default again.
13. In Windows Explorer, verify that Firefox is not the default PDF handler. (The feature is enabled, but another browser is not the existing default, so we should leave the PDF default alone.)

Verify functionality (elevated install)

Please repeat this with an elevated (C:\Program Files\...) installation.

Verify functionality (upgrade)

Please repeat this with a Firefox Beta 99 that updates to 100.0b1. (This tests the post-update process.) This can be an elevated or an un-elevated install, it should not make a difference.

Windows 7

None of the set-to-default functionality for PDFs works on Windows 7. But please verify that on Windows 7, if Firefox is set as the default PDF handler (using the Open With ... option, for example), then the file type description and the icon look reasonable.

Nick - it looks like you should be assigned here. Also setting my best guess at priority/severity.

There are 3 pieces left to really finish this up:

1. Bug 1767967 - Support earlier versions of Windows 10
2. Bug 1764290 - Migrate existing users who have Firefox set as their default PDF viewer to the new PDF ProgID
3. Bug 1762172 - Bring the new PDF iconography and copy to MSIX packages