Our Unix version is undergoing a lot of radical changes for the 10.5 release. It has been mentioned earlier that we are removing our dependency on the Qt libraries. By doing this, we hope to integrate better with the popular desktop environments out there, and we allow Opera to run without the need for a library that might or might not be installed on your system.
This means that you can run Opera without any graphical toolkit installed if you want to (plain X11), but if you do have toolkits installed, Opera will try to load and use them to integrate into the environment. Currently we are focusing on getting support for Gnome/GTK+ and KDE4/Qt4 into 10.5. The work on KDE4 integration is not at a stage yet where we think it can be used, so this pre-alpha release only has support for GTK. As a work in progress, you will notice that not all UI elements conform to their GTK specifications yet.
Some features, such as printing and drag-and-drop functionality, are missing from this build.
Because this is a pre-alpha release, we don't recommend you to install it over your existing Opera installation. This is why we are releasing only non-installable tarballs instead of installable packages. To run Opera, extract the tarball and run './opera' from the main directory.