[Broadway](#broadway-envar) GDK backends use some additional
environment variables.
+Note that environment variables are generally used for debugging
+purposes. They are not guaranteed to be API stable, and should not
+be used for end-user configuration and customization.
+
### `GTK_DEBUG`
This variable can be set to a list of debug options, which cause GTK to
`snapshot`
: Include debug render nodes in the generated snapshots
+`invert-text-dir`
+: Invert the text direction, compared to the locale
+
The special value `all` can be used to turn on all debug options.
The special value `help` can be used to obtain a list of all
supported debug options.
`gl-disable`
: Disable OpenGL support
-`gl-software`
-: Force OpenGL software rendering
-
-`gl-texture-rect`
-: Use the OpenGL texture rectangle extension, if available
-
`gl-legacy`
: Use a legacy OpenGL context
`gl-gles`
: Use a GLES OpenGL context
+`gl-egl`
+: Use an EGL context on X11 or Windows
+
+`gl-glx`
+: Use GLX on X11
+
+`gl-wgl`
+: Use WGL on Windows
+
`vulkan-disable`
: Disable Vulkan support
`vulkan-validate`
: Load the Vulkan validation layer, if available
+`default-settings`
+: Force default values for xsettings
+
+`high-depth`
+: Use high bit depth rendering if possible
+
The special value `all` can be used to turn on all debug options. The special
value `help` can be used to obtain a list of all supported debug options.