Since you're using docker, also ensure your containers are set to rotate log files. By default, docker does not enable this, but you can change the defaults. Otherwise you can quickly get gigabytes of logs that eat up space.
There is no single standard DE on Linux. KDE and Gnome are the biggest ones, and most distros ship with flavors for either. So is KDE non-standard if I install it on regular Ubuntu (which ships with Gnome)? And besides, as the commenter above said, wlroots is one of the few big participants in deciding the wayland protocols, so they are most certainly standard, as standard as any wayland compositor.
Opening a new terminal should work, since those commands you posted affect just the running shell. If not, you broke something else.
Edit: Assuming you pit that export line into ~/.bashrc, just remove it. You might need to enable showing hidden files in your file explorer, them edit it as a text file.
The value of this header cannot be set via JavaScript, so the server can assume that a) if this header is present, then the client is a web browser, and b) the value of the header can be trusted.
This is already obviously wrong. It cannot be set from JavaScript, true, but any other client including scrapers may set it. So (a) is completely untrue, it being present implies nothing and (b) is also untrue by the nature of networking. You can only assume that it either came from a browser without manipulation, in which case the value can be trusted, or from an external source, in which case the attacker may set an arbitrary value.
I don't think you need to do anything special here. So long as the client enables TOR on their device (or just the browser), all traffic including WebRTC will be routed through the onion network, like with a VPN. Your server will only see the IP of the exit node.
Basically anything low level. When you need a byte, you also don't use a int, you use a uint8_t (reminder that char is actually not defined to be signed or unsigned, "Plain char may be signed or unsigned; this depends on the compiler, the machine in use, and its operating system"). Any time you need to interact with another system, like hardware or networking, it is incredibly important to know how many bits the other side uses to avoid mismatching.
For purely the size of an int, the most famous example is the Ariane 5 Spaceship Launch, there an integer overflow crashed the space ship. OWASP (the Open Worldwide Application Security Project) lists integer overflows as a security concern, though not ranked very highly, since it only causes problems when combined with buffer accesses (using user input with some arithmetic operation that may overflow into unexpected ranges).
Very often you need to choose a type based on the data it needs to hold. If you know you'll need to store numbers of a certain size, use an integer type that can actually hold it, don't make it dependent on a platform definition. Always using int can lead to really insidious bugs where a function may work on one platform and not on another due to overfloe
That looks like a loading indicator of your client, especially if the gradient of the box is moving