There are a couple ways to check the download location.

• After you download something, press Ctrl-J to open the Downloads page. For any of the items you recently downloaded, click on the folder icon on the far right. It should show you in your file explorer where it downloaded.
• Go to about:config and accept the warning. In the search bar at the top, type browser.download.lastDir and the file path will be the last location you downloaded to.
• In Options > General, scroll to Files and Applications. Check "Always ask you where to save files" so whenever you download something through Firefox, you can put it exactly where you want.

• After you download something, press Ctrl-J to open the Downloads page. For any of the items you recently downloaded, click on the folder icon on the far right. It should show you in your file explorer where it downloaded.

Right, that is not working in flatpak version.

• Go to about:config and accept the warning. In the search bar at the top, type browser.download.lastDir and the file path will be the last location you downloaded to.

It' set to my regular Downloads directory: /home/me/Downloads.

• In Options > General, scroll to Files and Applications. Check "Always ask you where to save files" so whenever you download something through Firefox, you can put it exactly where you want.

When I do that it prompts me with the following selected directory: /run/user/1000/doc/beb81e18, then I have to select /home/me/Downloads everytime. What I want is that it works like the regular version, downloading to my default directory.