How did I end up with these unknown folders/files on my external drive?

Here is snapshot of my external drive. I never store any files directly in its root folder yet I have bunch of files eula.###.txt and others for example install.exe and similar files. How did they get there?

More important there are a number folders with numeric names. These are all zero bytes folders and has nothing inside them. What does this mean and how did it get there?

Note: I have masked my own files with boxes.

These are leftover files from installations of Microsoft Visual C++ Redistributable for Visual Studio. I had them too. You can safely delete them.

https://support.microsoft.com/en-gb/help/950683/vcredist-from-vc-2008-installs-temporary-files-in-root-directory