Put your hand up if your browser's "Downloads" folder is packed with random stuff? OK, I'm sure some people diligently organise theirs, but for the rest of us, it would be nice if you could sort files ahead of time. "Save In", an add-on for Firefox and Chrome, lets you save files to sub-directories so you can keep that Downloads folder nice and clean.
For security reasons, you can only save into sub-directories in the main Downloads folder. However, the extension's creator does provide a workaround, depending on your operating system:
The WebExtension API only allows saving into directories relative to the default download directory. Symlinks can be used to get around this limitation:
Windows: mklink /D C:\path\to\symlink D:\path\to\actual macOS/Unix: ln -s /path/to/actual /path/to/symlink
Make sure the actual directories exist, or downloads will silently fail.
When you have it configured, you can right-click links, navigate to the "Save In..." item in the context menu and it'll expand to show the sub-directories. Select the one you want and it'll be saved the that location.