--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -2786,17 +2786,23 @@ pref("layout.css.font-variations.enabled
 
 // Are sets of prefixed properties supported?
 pref("layout.css.prefixes.border-image", true);
 pref("layout.css.prefixes.transforms", true);
 pref("layout.css.prefixes.transitions", true);
 pref("layout.css.prefixes.animations", true);
 pref("layout.css.prefixes.box-sizing", true);
 pref("layout.css.prefixes.font-features", true);
+
+// Is -moz-prefixed gradient functions enabled?
+#ifdef NIGHTLY_BUILD
+pref("layout.css.prefixes.gradients", false);
+#else
 pref("layout.css.prefixes.gradients", true);
+#endif
 
 // Are webkit-prefixed properties & property-values supported?
 pref("layout.css.prefixes.webkit", true);
 
 // Are "-webkit-{min|max}-device-pixel-ratio" media queries supported?
 // (Note: this pref has no effect if the master 'layout.css.prefixes.webkit'
 // pref is set to false.)
 pref("layout.css.prefixes.device-pixel-ratio-webkit", false);