The Firefox Library is the Bookmarks/History/Download Manager.

• Bookmarks >Show All Bookmarks
• History > Show All History
• https://support.mozilla.org/kb/how-do-i-use-bookmarks

The Downloads folder in the Library only shows a list of files that you have downloaded.
You can right-click an entry in the Downloads folder and choose "Open Containing Folder" to go to the folder where you initially stored this file.
If the "Open" and "Open Containing Folder" entries are grayed (disabled) then this means that the file is no longer in that folder, but have been (re)moved, possibly by anti-virus software if you didn't do this.

Once you are in that folder then you can copy/move the file in Windows Explorer.

When I right click the entry in the Downloads folder and choose Open Containing Folder--nothing happens and no, the entry was not grayed out. Now what?

same problems here - how can I just switch back to the Downloads list instead of this stupid Chrome rip-off Library that just adds pointless extra steps to downloading and opening anything?

when I click on the "Open in Folder" it just opens the Downloads Library in another tab - it won't actually open the downloads folder on my hard drive anymore, and after files have been deleted there seems to be no way to then remove them from the Library. When I click on files in the Library, they often will not open from there - I have to manually search my hard drive for the downloaded file, then click it there and it opens fine - I do not understand the advantage of this "improvement", and it seems to slow down Firefox as well.

whatever happened to "Keep it simple" or "just make it work", instead of philosophies like "just copy whatever Chrome is doing" and "let's make some more pointless changes to justify a new version number"?