Fixing header levels and the structure

Author: viictor1

en/faq/linux.md

@@ -18,6 +18,12 @@ Please follow the steps provided on our [installation page](../installation.md).
 
 You might see the error message `Error: Could not find or load main class org.jabref.JabRefMain`. This means, you do not have [JavaFX](https://en.wikipedia.org/wiki/JavaFX) support activated in your Java runtime environment. This typically happens if you use [OpenJDK](http://openjdk.java.net/), where one needs to setup [OpenJFX](https://wiki.openjdk.java.net/display/OpenJFX/Main) separately.
 
+### Wayland-based systems
+
+JabRef relies on [XWayland](https://packages.debian.org/stable/xwayland) to run in Wayland environments. If your system is missing this dependency, the application will fail to launch (often showing an `Unable to open DISPLAY` error). To fix this, simply install XWayland using your distribution's package manager.
+
+For example, on Debian/Ubuntu systems, run: `sudo apt install xwayland`
+
 ## I am on Debian/Ubuntu and clicking on the JabRef icon works, but I cannot start JabRef from the command line. What is wrong?
 
 You have several Java Virtual Machines installed, and under the command line the wrong one is chosen. Have a look at the previous question that tells you how to change the virtual machine used.