diff --git a/gfx/thebes/gfxUserFontSet.h b/gfx/thebes/gfxUserFontSet.h
index 3a13573ac..2570bd711 100644
--- a/gfx/thebes/gfxUserFontSet.h
+++ b/gfx/thebes/gfxUserFontSet.h
@@ -191,14 +191,23 @@ public:
         FLAG_FORMAT_WOFF           = 1 << 6,
         FLAG_FORMAT_WOFF2          = 1 << 7,
 
+        FLAG_FORMAT_OPENTYPE_VARIATIONS = 1 << 8,
+        FLAG_FORMAT_TRUETYPE_VARIATIONS = 1 << 9,
+        FLAG_FORMAT_WOFF_VARIATIONS     = 1 << 10,
+        FLAG_FORMAT_WOFF2_VARIATIONS    = 1 << 11,
+
         // the common formats that we support everywhere
         FLAG_FORMATS_COMMON        = FLAG_FORMAT_OPENTYPE |
                                      FLAG_FORMAT_TRUETYPE |
                                      FLAG_FORMAT_WOFF     |
-                                     FLAG_FORMAT_WOFF2,
+                                     FLAG_FORMAT_WOFF2    |
+                                     FLAG_FORMAT_OPENTYPE_VARIATIONS |
+                                     FLAG_FORMAT_TRUETYPE_VARIATIONS |
+                                     FLAG_FORMAT_WOFF_VARIATIONS     |
+                                     FLAG_FORMAT_WOFF2_VARIATIONS,
 
         // mask of all unused bits, update when adding new formats
-        FLAG_FORMAT_NOT_USED       = ~((1 << 8)-1)
+        FLAG_FORMAT_NOT_USED       = ~((1 << 12)-1)
     };
 
 
diff --git a/layout/inspector/nsFontFace.cpp b/layout/inspector/nsFontFace.cpp
index abf9f6439..03ac0d583 100644
--- a/layout/inspector/nsFontFace.cpp
+++ b/layout/inspector/nsFontFace.cpp
@@ -178,6 +178,18 @@ nsFontFace::GetFormat(nsAString & aFormat)
     if (formatFlags & gfxUserFontSet::FLAG_FORMAT_WOFF2) {
       AppendToFormat(aFormat, "woff2");
     }
+    if (formatFlags & gfxUserFontSet::FLAG_FORMAT_OPENTYPE_VARIATIONS) {
+      AppendToFormat(aFormat, "opentype-variations");
+    }
+    if (formatFlags & gfxUserFontSet::FLAG_FORMAT_TRUETYPE_VARIATIONS) {
+      AppendToFormat(aFormat, "truetype-variations");
+    }
+    if (formatFlags & gfxUserFontSet::FLAG_FORMAT_WOFF_VARIATIONS) {
+      AppendToFormat(aFormat, "woff-variations");
+    }
+    if (formatFlags & gfxUserFontSet::FLAG_FORMAT_WOFF2_VARIATIONS) {
+      AppendToFormat(aFormat, "woff2-variations");
+    }
   }
   return NS_OK;
 }
diff --git a/layout/style/FontFaceSet.cpp b/layout/style/FontFaceSet.cpp
index cb968e248..b27fb3d9b 100644
--- a/layout/style/FontFaceSet.cpp
+++ b/layout/style/FontFaceSet.cpp
@@ -1130,6 +1130,15 @@ FontFaceSet::FindOrCreateUserFontEntryFromFontFace(const nsAString& aFamilyName,
               face->mFormatFlags |= gfxUserFontSet::FLAG_FORMAT_EOT;
             } else if (valueString.LowerCaseEqualsASCII("svg")) {
               face->mFormatFlags |= gfxUserFontSet::FLAG_FORMAT_SVG;
+            } else if (valueString.LowerCaseEqualsASCII("woff-variations")) {
+              face->mFormatFlags |= gfxUserFontSet::FLAG_FORMAT_WOFF_VARIATIONS;
+            } else if (Preferences::GetBool(GFX_PREF_WOFF2_ENABLED) &&
+                       valueString.LowerCaseEqualsASCII("woff2-variations")) {
+              face->mFormatFlags |= gfxUserFontSet::FLAG_FORMAT_WOFF2_VARIATIONS;
+            } else if (valueString.LowerCaseEqualsASCII("opentype-variations")) {
+              face->mFormatFlags |= gfxUserFontSet::FLAG_FORMAT_OPENTYPE_VARIATIONS;
+            } else if (valueString.LowerCaseEqualsASCII("truetype-variations")) {
+              face->mFormatFlags |= gfxUserFontSet::FLAG_FORMAT_TRUETYPE_VARIATIONS;
             } else {
               // unknown format specified, mark to distinguish from the
               // case where no format hints are specified