In Settings I have "Save files to" set to Desktop. Under Applications, I have PDF Files set to "Save File." If I download any other type of file, it is saved to the Desktop, as instructed. However, when I open Firefox, the Save dialog shows PDF files will be saved to Downloads. If I change it to Desktop, the file will be saved to the Desktop. Other types of file, as mentioned above, show Desktop as the default in the Save dialog. Once I set Desktop for a PDF file, it will be remembered until I close and reopen Firefox. It will then switch back to the Downloads folder, but again, only for PDF files. Why? This is something that has stated happening sometime over the last couple of months.

Windows 10 Pro 22H2, October 2025 patches installed. Firefox v144.0.2