Damn, ok, sorry I feel dumb haha. That's great actually, nice work! I'll keep it installed.

I'm thinking of doing an extension with all these things, and also bulk ebook zip export and other stuff like that (on bundles or the whole collection). Maybe you wanna help me?

Interesting idea about the extension.
As for the ebooks, I actually made the PowerShell script to download them or any DRM-Free files from humble bundle.

It requires Powershell v3+ which is available from Windows 8+ (Windows 7 requires newer PowerShell, link in script readme). You can find more about it here:

https://www.reddit.com/r/humblebundles/comments/9qqch0/humble_bundle_drmfree_bulk_downloader/

All of them will be downloaded into the folder which looks like this: bundleName\DRMFreeFileTitle\DRMFreeFile.ext

Working on an export script that runs in the browser directly. I don't run Windows so I wouldn't be able to use your script anyway haha. I'll post my script on this sub when I finish it.