Windows Subsystem for Linux (WSL)

What does the Windows Subsystem for Linux let you do that a virtual machine setup does not, and roughly when did it arrive?

A colleague says WSL1 already ran a Linux kernel and WSL2 just made it faster. Where is that wrong, and what actually changed in WSL2?

Before WSLg, how could you show a Linux GUI program on Windows, and what did WSLg change about that?

Someone runs Docker Desktop on Windows and assumes it has nothing to do with WSL. Why is that assumption off?

What are the Windows edition and setup requirements to get WSL running?

Two Windows users on the same PC both want Ubuntu under WSL. Why can't they just share the one installation, and what privileges does the WSL user get?

You open three WSL windows of the same distribution. Are these like three separate Docker containers, and how would you tell?

systemctl fails on an older WSL2 Ubuntu install. How do you enable systemd, and what has to happen for it to take effect?

You enable a cron job and an SSH server in WSL, then close the last WSL window and wonder why nothing runs. What happened?

iptables, nmap, and dmesg fail in a WSL distribution. What do these commands have in common, and what's the fix?

From WSL you reach Windows files under /mnt/c. What technical difference sits behind that mount in WSL1 versus WSL2, and what surprises users about the permissions?

You start an HTTP server inside WSL2 and want to browse it from Windows by host name. Why doesn't that work, and what has to be done instead each time?

Setting localhostForwarding=true makes WSL2 services reachable via localhost on Windows. What does turning it on cost you?

The wsl command lets you jump straight to a distro's root shell with no password. How do you do it, and why is that a security concern?

How do you check which WSL version a distribution is running, and how do you convert it between WSL1 and WSL2?

Among wsl -t, wsl --shutdown, and wsl --unregister, which one is destructive, and how do the other two differ?

You want WSL2 to stop hogging your machine's cores and RAM. Which file caps that, and what has to happen for the change to apply?

There are two WSL config files with similar names. What's the difference between .wslconfig and /etc/wsl.conf, and what does each configure?

Your WSL2 distro's 256 GiB isn't enough. Where does its disk actually live and how do you enlarge it?

You want to open your WSL home directory from Windows Explorer, and you're unsure where to keep working files. What's the path, and how does the WSL1-vs-WSL2 storage advice flip?

Where does a WSL2 distribution actually store its Linux files, and what upper size limit does that storage have by default?

Can you run a full GNOME desktop through WSLg, or is it meant for something narrower?

Why can WSL1 be reached at the Windows machine's own IP while WSL2 usually can't be seen from other machines on your LAN?