What is the location that websites use when Chrome alerts with ".. wants to store files on this device" and where can I change it?

Question

At the moment there are some websites where in chrome, if I go to them and click to download a file, I get this screen saying that blah-website 'wants to store files on this device".

I understand that this alert is now something Chrome does or may do Website Wants to Store Files on this Device? (Chrome)

If I click allow then a progress bar appears at the top

But I don't see where the file is downloading too. I don't see it in the folder set in Chrome as my downloads folder.

Where is it being stored while it downloads, and can I change this location?

If it's a big file I want it stored on an external drive.

Answer 1

The popup you are referring too is a result of a website trying to use the FileSystem API.

Chrome on windows currently stores these files in %LocalAppData%\Google\Chrome\User Data\Default\File System with different folders for each site origin that requested the API.