In commit e7e0aea6958b1419a5e72c85da0e0f920d36fb53, this was added with the wrong name -- the "lrfviewer" application doesn't have a hyphenated name, oddly enough, even though it is in fact "ebook-viewer" not "ebookviewer". On the other hand, it's probably not worth fixing the inconsistency, because changing desktop filenames can be (a bit) disruptive if people have pinned or modified them, and it's not worth it just for a stray hyphen. Changing the actual program executable name is even less worth it...
calibre

calibre is an e-book manager. It can view, convert, edit and catalog e-books in all of the major e-book formats. It can also talk to e-book reader devices. It can go out to the internet and fetch metadata for your books. It can download newspapers and convert them into e-books for convenient reading. It is cross platform, running on Linux, Windows and macOS.
For more information, see the calibre About page.
Screenshots
Usage
See the User Manual.
Development
Setting up a development environment for calibre.
A tarball of the source code for the current calibre release.
Bugs
Bug reports and feature requests should be made in the calibre bug tracker at Launchpad. GitHub is only used for code hosting and pull requests.
Support calibre
calibre is a result of the efforts of many volunteers from all over the world. If you find it useful, please consider contributing to support its development. Donate to support calibre development.
Building calibre binaries
See Build instructions for instructions on how to build the calibre binaries and installers for all the platforms calibre supports.