diff --git a/doc/flatpak-metadata.xml b/doc/flatpak-metadata.xml
index 3490cfe41..ae62764aa 100644
--- a/doc/flatpak-metadata.xml
+++ b/doc/flatpak-metadata.xml
@@ -610,6 +610,16 @@
branch in 0.8.3.
+
+ (string)
+
+ A condition that must be false for the extension to be considered unused when
+ pruning. For example, flatpak uninstall --unused uses
+ this information. The only currently recognized value is active-gl-driver,
+ which is true if the name of the active GL driver matches the extension
+ point basename. Available since 0.11.8.
+
+ (string)