You have most of these, or at least very similar versions, in Plasma/KDE today: > Document Database This is what Akonadi was when when it came out for 4.x. Ne

You have most of these, or at least very similar versions, in Plasma/KDE today: > Document Database This is what Akonadi was when when it came out for 4.x. Nepomuk was the semantic search framework so you could rate/tag/comments on files and search by them. They had some performance problems and were not very well received. Nepomuk has been superseded by Baloo, so you can still tag/rate/comment files now. Most KDE apps also use KIO slaves: https://www.maketecheasier.com/quick-easy-guide-to-kde-kio-slaves/ https://www.maketecheasier.com/quick-easy-guide-to-kde-kio-s... > System Side Semantic Keybindings > Windows Plasma 4 used to have compositor-powered tabs for any apps. Can't say if it will be coming back to Plasma 5. Automatic app-specific colors (and other rules) are possible now. > Smart copy and paste The clipboard plasmoid in the system tray has multiple items, automatic actions for what to do with different types of content and can be pinned, to remain visible. > Working Sets These are very similar to how Activities work. Don't seem to be very popular.