When I emailed them about this in October of 2023, they gave me the following dismissive answer:

"We are only offering pdfs in our Humble Bundle offerings. Sorry to disappoint."

Sadly, these days complaints need to be very public for them to have any effect so if any of you are on social media, bring this issue to Dark Horse's -- and its followers' -- attention over there.

I also skipped the earlier Hellboy bundle because I had those comics on Dark Horse Digital. DRM-free only from now on for me, I've learned my lesson.

Yeah, it seems they took out the "cbz" part of the bundle description now so there's probably not much hope, unfortunately.

I was excited to see a new IDW TMNT bundle on Humble:

https://www.humblebundle.com/books/teenage-mutant-ninja-turtles-feat-last-ronin-books

but... seems it's DRM-ed and forced using Kobo to access the books. Shame.

I remember that IDW books were available DRM-free on Humble bundle in the past. Hope that didn't change for good.

Removing Kobo DRM is a bit painful at first, but not too bad after you've done it a few times.

It requires making a Kobo account downloading a .ascm file.Then downloading Adobe digital editions to convert to a DRM ebook. Then installing DeDRM as plugin in Calibre and finally adding the book to Calbre to remove the DRM.

Look for a guide and it will explain it better than me.

The only store I haven't figured out how to remove the DRM yet is Bookwalker so if someone has any tips, please share.

This is the first-time I'm also seeing a book bundle being sold on Humble with DRM. Has this ever happened before?

That's certainly possible. What's the point of doing all that after paying for those comics, though? In that case, I might as well just go to the "high seas" and get it "DRM-free" for free (without much effort too).

Yes. I remember there was at least one other Kobo bundle not too long ago (I think it was manga?), also there was a "Valerian" bundle through Izneo (which I bought nonetheless) a few years back. Probably a few more.

same, this bundle is so disappointing

Often the quality is higher or there is no good option available otherwise. I also like to support authors / smaller publishers on a non-Amazon alternative even if it has DRM, especially for more niche titles.

It's a totally valid reason but I just really don't like DRM. :-D Besides, Adobe Digital Editions and the Kobo desktop app aren't supported on Linux.