Diễn đàn hỗ trợ Firefox

Files previously downloaded by earlier versions of Firefox as .webp cannot be opened by 115.19.0esr. Firefox keeps asking what application to use, and I have selected Firefox. When I OK the selection, it opens a blank screen with the same question (what application to use). This goes on forever, opening a new blank tab again and again, each with the same question about what application to use. My old Mac operating system 10.13.6 retains its original version of Preview installed, and of course, that version of Preview does not know how to open .webp files.

When I want to save a document to the desktop, I click on File and select save page as. Recently there was a change to the format options. I was able to save my documents to the desktop and in format was pdf which I selected and saved. Now the format options are Test Files, Web page HTML only and Web page complete. I have no idea what happened to the PDF format and there is no way that I know of that I can insert that option. Keep in mind that I am an 85 year old woman with limited technology knowledge. Thank you!