Given that the saved searches action and the saved search button on the search bar now do the same thing, it seems reasonable to allow the user to choose whether the saved search button shows. I went from there to "Why not allow adding other buttons to the bar?" There is a lot of available real estate on that bar. This commit does that using a new toolbar in preferences / toolbars. I didn't use a QToolBar, instead constructing a 'classic' toolbar in an QHBoxLayout. That gave me more control over the look and placement. And also, I had no end of trouble trying to work through how to use a QToolBar that isn't attached to a QMainWIndow. In the process I removed the legacy Saved Search combo box, its associated buttons, and the tweak. I am sure there are some people still using the years-old interface and that they will complain. I can accept that, given that the button is better in almost every way.
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.