As a Linux user, it unfortunately doesn't have a definitive anything. Say you want to write a GUI app. On Windows, you've got Win32. It's old, but it'll still

As a Linux user, it unfortunately doesn't have a definitive anything. Say you want to write a GUI app. On Windows, you've got Win32. It's old, but it'll still work and look new. MacOS you have Cocoa. Linux, you have Xlib. Wait, that doesn't provide enough. We have to use a toolkit, like Gtk or Qt. Which one if we want to look integrated? How do we integrate 3D APIs? Then there's Wayland. You want to use that instead because X is deprecated. But there's no extensive API--it's basically only a way of putting rectangles on the screen. You have nothing to get you started unless you stick hard to Gtk, Qt, or do really rudimentary graphics, and cross-compatibility is really ugly.