diff --git a/src/fontra/backends/copy.py b/src/fontra/backends/copy.py
index 2fb66d57e..77fc8e5f1 100644
--- a/src/fontra/backends/copy.py
+++ b/src/fontra/backends/copy.py
@@ -14,7 +14,7 @@ async def copyFont(
     sourceBackend, destBackend, *, glyphNames=None, numTasks=1, progressInterval=0
 ):
     await destBackend.putGlobalAxes(await sourceBackend.getGlobalAxes())
-    await destBackend.putFontLib(await sourceBackend.getFontLib())
+    await destBackend.putCustomData(await sourceBackend.getCustomData())
     glyphMap = await sourceBackend.getGlyphMap()
     glyphNamesInFont = set(glyphMap)
     glyphNamesToCopy = sorted(
diff --git a/src/fontra/backends/designspace.py b/src/fontra/backends/designspace.py
index ea184fc78..ad5c56741 100644
--- a/src/fontra/backends/designspace.py
+++ b/src/fontra/backends/designspace.py
@@ -560,10 +560,10 @@ async def putGlobalAxes(self, axes):
     async def getUnitsPerEm(self):
         return self.defaultFontInfo.unitsPerEm
 
-    async def getFontLib(self):
+    async def getCustomData(self):
         return deepcopy(self.dsDoc.lib)
 
-    async def putFontLib(self, lib):
+    async def putCustomData(self, lib):
         self.dsDoc.lib = deepcopy(lib)
         self.dsDoc.write(self.dsDoc.path)
 
diff --git a/src/fontra/backends/fontra.py b/src/fontra/backends/fontra.py
index e5801f682..9fcff8ca5 100644
--- a/src/fontra/backends/fontra.py
+++ b/src/fontra/backends/fontra.py
@@ -95,10 +95,10 @@ async def putGlobalAxes(self, axes):
         self.fontData.axes = deepcopy(axes)
         self._scheduler.schedule(self._writeFontData)
 
-    async def getFontLib(self):
+    async def getCustomData(self):
         return deepcopy(self.fontData.customData)
 
-    async def putFontLib(self, customData):
+    async def putCustomData(self, customData):
         self.fontData.customData = deepcopy(customData)
         self._scheduler.schedule(self._writeFontData)
 
diff --git a/src/fontra/backends/opentype.py b/src/fontra/backends/opentype.py
index c67c19160..127a4a434 100644
--- a/src/fontra/backends/opentype.py
+++ b/src/fontra/backends/opentype.py
@@ -101,8 +101,8 @@ async def getGlobalAxes(self):
     async def getUnitsPerEm(self):
         return self.font["head"].unitsPerEm
 
-    async def getFontLib(self):
-        return []
+    async def getCustomData(self):
+        return {}
 
 
 def tuplifyLocation(loc):
diff --git a/src/fontra/client/core/font-controller.js b/src/fontra/client/core/font-controller.js
index 294642fb5..ac8bd3a05 100644
--- a/src/fontra/client/core/font-controller.js
+++ b/src/fontra/client/core/font-controller.js
@@ -42,7 +42,7 @@ export class FontController {
     this._rootObject["glyphMap"] = getGlyphMapProxy(glyphMap, this.characterMap);
     this._rootObject["axes"] = await this.font.getGlobalAxes();
     this._rootObject["unitsPerEm"] = await this.font.getUnitsPerEm();
-    this._rootObject["lib"] = await this.font.getFontLib();
+    this._rootObject["customData"] = await this.font.getCustomData();
     this._rootClassDef = (await getClassSchema())["Font"];
     this._resolveInitialized();
   }
@@ -71,8 +71,8 @@ export class FontController {
     return this._rootObject["unitsPerEm"];
   }
 
-  get fontLib() {
-    return this._rootObject["lib"];
+  get customData() {
+    return this._rootObject["customData"];
   }
 
   getCachedGlyphNames() {
diff --git a/src/fontra/core/fonthandler.py b/src/fontra/core/fonthandler.py
index d05347828..00b2d7ab3 100644
--- a/src/fontra/core/fonthandler.py
+++ b/src/fontra/core/fonthandler.py
@@ -36,7 +36,7 @@ def remoteMethod(method):
 backendAttrMapping = [
     ("axes", "GlobalAxes"),
     ("glyphMap", "GlyphMap"),
-    ("lib", "FontLib"),
+    ("customData", "CustomData"),
     ("unitsPerEm", "UnitsPerEm"),
 ]
 
@@ -209,8 +209,8 @@ async def getUnitsPerEm(self, *, connection):
         return await self.getData("unitsPerEm")
 
     @remoteMethod
-    async def getFontLib(self, *, connection):
-        return await self.getData("lib")
+    async def getCustomData(self, *, connection):
+        return await self.getData("customData")
 
     def _getClientData(self, connection, key, default=None):
         return self.clientData[connection.clientUUID].get(key, default)
diff --git a/src/fontra/views/editor/cjk-design-frame.js b/src/fontra/views/editor/cjk-design-frame.js
index 5c088846d..e9e81f02c 100644
--- a/src/fontra/views/editor/cjk-design-frame.js
+++ b/src/fontra/views/editor/cjk-design-frame.js
@@ -66,7 +66,7 @@ export class CJKDesignFrame {
       this.cjkDesignFrameParameters = makeParametersFromGlyph(frameGlyph, unitsPerEm);
     } else {
       const legacyParameters =
-        this.sceneController.sceneModel.fontController.fontLib[
+        this.sceneController.sceneModel.fontController.customData[
           "CJKDesignFrameSettings"
         ];
       if (legacyParameters) {
diff --git a/src/fontra/views/editor/panel-designspace-navigation.js b/src/fontra/views/editor/panel-designspace-navigation.js
index 3a3c14ae4..803a0b63c 100644
--- a/src/fontra/views/editor/panel-designspace-navigation.js
+++ b/src/fontra/views/editor/panel-designspace-navigation.js
@@ -277,7 +277,7 @@ export default class DesignspaceNavigationPanel extends Panel {
     ];
 
     const statusFieldDefinitions =
-      this.sceneController.sceneModel.fontController.fontLib[
+      this.sceneController.sceneModel.fontController.customData[
         FONTRA_STATUS_DEFINITIONS_KEY
       ];
 
diff --git a/test-py/test_font.py b/test-py/test_font.py
index 52fe04537..84c7d6c01 100644
--- a/test-py/test_font.py
+++ b/test-py/test_font.py
@@ -1022,9 +1022,9 @@ async def test_getGlobalAxes(testFontName, expectedGlobalAxes):
 
 @pytest.mark.asyncio
 @pytest.mark.parametrize("testFontName, expectedLibLen", getLibTestData)
-async def test_getFontLib(testFontName, expectedLibLen):
+async def test_getCustomData(testFontName, expectedLibLen):
     font = getTestFont(testFontName)
-    lib = await font.getFontLib()
+    lib = await font.getCustomData()
     assert expectedLibLen == len(lib)