Hello,

I have just installed the okular-extra-backends package and
am unable to open .epub files with Okular, which the package
description says I should be able to do.

When I try to open any ePub document I get a dialog saying:
"Could not open /path/to/myfile.epub" (replace with proper path)

The main UI window also indicates: "Can not find a plugin which is
able to handle the document being passed".

Let me know what I can do to help fix and test this. After installing
the extra-backends package ePub files have been associated with
Okular, which they weren't before so it's further indication that
the program should be able to handle them.

The files open fine on fbreader.

I'd also like to question why isn't the extra-backends package
recommended instead of suggested (which would make it install
by default on some package managers like aptitude). Especially
due to the epub capability I think it should be recommended, as
I see many people on the web ask about epub readers for Linux
and Okular's premise of being a all-in-one reader makes it perfect
as an ebook reader.

I just opened a few epub files and had no problems opening them and seeing
chapter headings.

Some of them didn't display the body text visibly but that's a different issue
to what was reported here.

I think that unless more evidence is provided this bug can be closed.  I will
file a separate bug about display issues if/when I find some PD/CC licenced
epub files to demonstrate the issue.