How to Determine the Currently Loaded Device Tree in Ubuntu?

You could install the tool called 'inxi' and run the command `sudo inxi -v 8`. This will provide you with detailed system information, including the parameters you're interested in.

The device tree's relevance largely depends on your processor architecture. For Intel or AMD processors, the Linux kernel typically doesn’t need a device tree since it can use configurations like ACPI to auto-configure. On the other hand, ARM or RISC-V processors usually require a device tree to outline hardware specifics, as there are no auto-configuration protocols at play. If your device mandates a device tree, the best way to find it would be by accessing the source code and build instructions, or you could check out the postmarketOS wiki for guidance. They're known for dealing with vendor kernels that aren't well documented. That being said, there’s a lot more to device trees like managing DTS and DTB files, and determining how to pass the correct tree to the kernel.

Try opening a terminal (you can use Ctrl + Alt + T) and executing the command `ls /dev`. It will show you a list of devices being used by the system. However, if you want to see who's logged in, you can run the command `who` and get your tty number, which can lead you into more explorations with just a command line interface.