Comment 18 for bug 1981163

(In reply to BOB from comment #10)
> 91.3.1 I don't use Firefox my system is Windows 10. I still can't open a pdf when composing an email to check contents. Never had that issue in prior versions.

What application do you expect it to open with?

What is your Action in General > Files & Attachments for the Portable Document Format (PDF) Content Type?

In 91.3.2 and previous 91.x.x versions, you should be repeatedly asked.