diff --git a/docs/ldml/tr35-keyboards.md b/docs/ldml/tr35-keyboards.md
index ac4c7961cb4..916671fe24c 100644
--- a/docs/ldml/tr35-keyboards.md
+++ b/docs/ldml/tr35-keyboards.md
@@ -204,8 +204,6 @@ Keyboard use can be challenging for individuals with various types of disabiliti
 
 **Arrangement:** The relative position of the rectangles that represent keys, either physically or virtually. A hardware keyboard has a static arrangement while a touch keyboard may have a dynamic arrangement that changes per language and/or layer. While the arrangement of keys on a keyboard may be fixed, the mapping of those keys may vary.
 
-**Base character:** The character emitted by a particular key when no modifiers are active. In ISO terms, this is group 1, level 1.
-
 **Base character:** The character emitted by a particular key when no modifiers are active. In ISO 9995-1:2009 terms, this is Group 1, Level 1.
 
 **Core keys:** also known as “alphanumeric” section. The primary set of key values on a keyboard that are used for typing the target language of the keyboard. For example, the three rows of letters on a standard US QWERTY keyboard (QWERTYUIOP, ASDFGHJKL, ZXCVBNM) together with the most significant punctuation keys. Usually this equates to the minimal set of keys for a language as seen on mobile phone keyboards.
@@ -1318,7 +1316,7 @@ A `layer` element describes the configuration of keys on a particular layer of a
 **Syntax**
 
 ```xml
-<layer id="layerId" modifier="{Set of Modifier Combinations}">
+<layer id="layerId" modifiers="{Set of Modifier Combinations}">
     ...
 </layer>
 ```
@@ -1340,11 +1338,11 @@ _Attribute_ `id` (required for `touch`)
 >
 > Must match `[A-Za-z0-9][A-Za-z0-9-]*`
 
-_Attribute:_ `modifier` (required for `hardware`)
+_Attribute:_ `modifiers` (required for `hardware`)
 
 > This has two roles. It acts as an identifier for the `layer` element for hardware keyboards (in the absence of the id= element) and also provides the linkage from the hardware modifiers into the correct `layer`.
 >
-> For hardware layouts, the use of `@modifier` as an identifier for a layer is sufficient since it is always unique among the set of `layer` elements in a keyboard.
+> For hardware layouts, the use of `@modifiers` as an identifier for a layer is sufficient since it is always unique among the set of `layer` elements in a keyboard.
 >
 > The set of modifiers must match `(none|([A-Za-z0-9]+)( [A-Za-z0-9]+)*)`
 >
@@ -1353,19 +1351,19 @@ _Attribute:_ `modifier` (required for `hardware`)
 **Syntax**
 
 ```xml
-<layer id="base"        modifier="none">
+<layer id="base"        modifiers="none">
     <row keys="a" />
 </layer>
 
-<layer id="upper"       modifier="shift">
+<layer id="upper"       modifiers="shift">
     <row keys="A" />
 </layer>
 
-<layer id="altgr"       modifier="altR">
+<layer id="altgr"       modifiers="altR">
     <row keys="a-umlaut" />
 </layer>
 
-<layer id="upper-altgr" modifier="altR shift">
+<layer id="upper-altgr" modifiers="altR shift">
     <row keys="A-umlaut" />
 </layer>
 ```
diff --git a/keyboards/3.0/fr-t-k0-azerty.xml b/keyboards/3.0/fr-t-k0-azerty.xml
index e0a5760f271..3cd15484617 100644
--- a/keyboards/3.0/fr-t-k0-azerty.xml
+++ b/keyboards/3.0/fr-t-k0-azerty.xml
@@ -90,7 +90,7 @@
 
 	<layers formId="iso">
 		<!-- in DTD: required if conformsTo ≥ 41 -->
-		<layer modifier="none">
+		<layer modifiers="none">
 			<row
 				keys="super-2 amp e-grave double-quote apos open-paren hyphen e-acute underscore c-cedilla a-acute close-paren equal" />
 			<row keys="a z e r t y u i o p caret dollar" />
@@ -99,7 +99,7 @@
 			<row keys="space" />
 		</layer>
 
-		<layer modifier="shift">
+		<layer modifiers="shift">
 			<row keys="1 2 3 4 5 6 7 8 9 0 degree plus" />
 			<row keys="A Z E R T Y U I O P umlaut pound" />
 			<row keys="Q S D F G H J K L M percent micro" />
diff --git a/keyboards/3.0/ja-Latn.xml b/keyboards/3.0/ja-Latn.xml
index 8c79ee4f373..b5364c5f928 100644
--- a/keyboards/3.0/ja-Latn.xml
+++ b/keyboards/3.0/ja-Latn.xml
@@ -13,14 +13,14 @@
 	</keys>
 
 	<layers formId="jis">
-		<layer modifier="none">
+		<layer modifiers="none">
 			<row keys="1 2 3 4 5 6 7 8 9 0 hyphen caret yen" />
 			<row keys="q w e r t y u i o p at open-square" />
 			<row keys="a s d f g h j k l semi-colon colon close-square" />
 			<row keys="z x c v b n m comma period slash underscore" />
 			<row keys="space"/>
 		</layer>
-		<layer modifier="shift">
+		<layer modifiers="shift">
 			<row keys="bang double-quote hash dollar percent amp apos open-paren close-paren 0 equal tilde pipe" /> <!-- 0 is repeated from "none" -->
 			<row keys="Q W E R T Y U I O P grave open-curly" />
 			<row keys="A S D F G H J K L plus asterisk close-curly" />
diff --git a/keyboards/3.0/mt-t-k0-47key.xml b/keyboards/3.0/mt-t-k0-47key.xml
index 3adc34aa684..62f90b47bce 100644
--- a/keyboards/3.0/mt-t-k0-47key.xml
+++ b/keyboards/3.0/mt-t-k0-47key.xml
@@ -44,7 +44,7 @@
 
     <!-- 47-key: MSA 100:2002, Appendix, figure A.1 -->
     <layers formId="us">
-        <layer modifier="none">
+        <layer modifiers="none">
             <row keys="c-tikka 1 2 3 4 5 6 7 8 9 0 hyphen equal" />
             <row keys="q w e r t y u i o p g-tikka h-maqtugha z-tikka" />
             <row keys="a s d f g h j k l semi-colon apos" />
@@ -52,7 +52,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="shift">
+        <layer modifiers="shift">
             <row keys="C-tikka bang at euro dollar percent caret amp asterisk open-paren close-paren underscore plus" />
             <row keys="Q W E R T Y U I O P G-tikka H-maqtugha Z-tikka" />
             <row keys="A S D F G H J K L colon double-quote" />
@@ -60,7 +60,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR">
+        <layer modifiers="altR">
             <row keys="grave gap gap pound gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap e-grave gap gap gap u-grave i-grave o-grave gap open-square close-square backslash" />
             <row keys="a-grave gap gap gap gap gap gap gap gap gap gap" />
@@ -68,7 +68,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR shift">
+        <layer modifiers="altR shift">
             <row keys="tilde gap gap gap gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap E-grave gap gap gap U-grave I-grave O-grave gap open-curly close-curly pipe" />
             <row keys="A-grave gap gap gap gap gap gap gap gap gap gap" />
diff --git a/keyboards/3.0/mt.xml b/keyboards/3.0/mt.xml
index f63e0845476..5dcc9ea5c35 100644
--- a/keyboards/3.0/mt.xml
+++ b/keyboards/3.0/mt.xml
@@ -47,7 +47,7 @@
 
      <!-- 48-key -->
     <layers formId="iso">
-        <layer modifier="none">
+        <layer modifiers="none">
             <row keys="c-tikka 1 2 3 4 5 6 7 8 9 0 hyphen equal" />
             <row keys="q w e r t y u i o p g-tikka h-maqtugha" />
             <row keys="a s d f g h j k l semi-colon hash" />
@@ -55,7 +55,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="shift">
+        <layer modifiers="shift">
             <row keys="C-tikka bang double-quote euro dollar percent caret amp open-paren close-paren underscore plus" />
             <row keys="Q W E R T Y U I O P G-tikka H-maqtugha" />
             <row keys="A S D F G H J K L colon at tilde" />
@@ -63,7 +63,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR">
+        <layer modifiers="altR">
             <row keys="grave gap gap pound gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap e-grave gap gap gap u-grave i-grave o-grave gap open-square close-square" />
             <row keys="a-grave gap gap gap gap gap gap gap gap gap gap gap" />
@@ -71,7 +71,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR shift">
+        <layer modifiers="altR shift">
             <row keys="not gap gap gap gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap E-grave gap gap gap U-grave I-grave O-grave gap open-curly close-curly" />
             <row keys="A-grave gap gap gap gap gap gap gap gap gap gap gap" />
diff --git a/keyboards/3.0/pcm.xml b/keyboards/3.0/pcm.xml
index 50a308b81c1..89994773f67 100644
--- a/keyboards/3.0/pcm.xml
+++ b/keyboards/3.0/pcm.xml
@@ -21,7 +21,7 @@
   </keys>
 
   <layers formId="iso">
-    <layer modifier="none">
+    <layer modifiers="none">
       <row keys="grave 1 2 3 4 5 6 7 8 9 0 hyphen equal" />
       <row keys="acute w e r t y u i o p open-square close-square" />
       <row keys="a s d f g h j k l odot edot slash" />
@@ -29,7 +29,7 @@
       <row keys="space" />
     </layer>
 
-    <layer modifier="shift">
+    <layer modifiers="shift">
       <row keys="grave bang at hash dollar naira percent amp asterisk open-paren close-paren underscore plus" />
       <row keys="A S D F G H J K L Odot Edot question" />
       <row keys="A S D F G H J K L Odot Edot" />
@@ -37,7 +37,7 @@
       <row keys="space" />
     </layer>
 
-    <layer modifier="caps">
+    <layer modifiers="caps">
       <row keys="backquote 1 2 3 4 5 6 7 8 9 0 hyphen equal" />
       <row keys="Q W E R T Y U I O P open-square close-square" />
       <row keys="A S D F G H J K L Odot Edot slash" />
diff --git a/keyboards/3.0/pt-t-k0-abnt2.xml b/keyboards/3.0/pt-t-k0-abnt2.xml
index 41060ea6403..ae1d7c4a74e 100644
--- a/keyboards/3.0/pt-t-k0-abnt2.xml
+++ b/keyboards/3.0/pt-t-k0-abnt2.xml
@@ -35,21 +35,21 @@
 		<key id="ordinal-masculine" output="º" />
 	</keys>
 	<layers formId="abnt2">
-		<layer modifier="none">
+		<layer modifiers="none">
 			<row keys="apos 1 2 3 4 5 6 7 8 9 0 hyphen equal" />
 			<row keys="q w e r t y u i o p d-acute open-square" />
 			<row keys="a s d f g h j k l c-cedilla d-tilde close-square" />
 			<row keys="backslash z x c v b n m comma period semi-colon slash" />
 			<row keys="space"/>
 		</layer>
-		<layer modifier="shift">
+		<layer modifiers="shift">
 			<row keys="double-quote bang at hash dollar percent d-umlaut amp asterisk open-paren close-paren underscore plus" />
 			<row keys="Q W E R T Y U I O P d-grave open-curly" />
 			<row keys="A S D F G H J K L C-cedilla d-tilde close-curly" />
 			<row keys="pipe Z X C V B N M open-angle close-angle colon question" />
 			<row keys="space"/>
 		</layer>
-		<layer modifier="altR">
+		<layer modifiers="altR">
 			<row keys="gap super-1 super-2 super-3 pound cent not gap gap gap gap gap section" />
 			<row keys="slash question degree gap gap gap gap gap gap gap gap ordinal-feminine" />
 			<row keys="gap gap gap gap gap gap gap gap gap gap gap ordinal-masculine" />
diff --git a/keyboards/dtd/ldmlKeyboard3.dtd b/keyboards/dtd/ldmlKeyboard3.dtd
index d74f948a44f..5222963d377 100644
--- a/keyboards/dtd/ldmlKeyboard3.dtd
+++ b/keyboards/dtd/ldmlKeyboard3.dtd
@@ -167,7 +167,7 @@ Please view the subcommittee page for the most recent information.
     <!--@TECHPREVIEW-->
 <!ATTLIST layer id NMTOKEN #IMPLIED >
     <!--@MATCH:any-->
-<!ATTLIST layer modifier NMTOKENS #IMPLIED >
+<!ATTLIST layer modifiers NMTOKENS #IMPLIED >
     <!--@MATCH:regex/(none|([A-Za-z0-9]+)( [A-Za-z0-9]+)*)-->
 
 <!ELEMENT row EMPTY >
diff --git a/keyboards/dtd/ldmlKeyboard3.xsd b/keyboards/dtd/ldmlKeyboard3.xsd
index 0c1a51fa45d..d8bfc470538 100644
--- a/keyboards/dtd/ldmlKeyboard3.xsd
+++ b/keyboards/dtd/ldmlKeyboard3.xsd
@@ -307,7 +307,7 @@ Note: DTD @-annotations are not currently converted to .xsd. For full CLDR file
         <xs:element maxOccurs="unbounded" minOccurs="0" ref="special"/>
       </xs:sequence>
       <xs:attribute name="id" type="xs:NMTOKEN"/>
-      <xs:attribute name="modifier" type="xs:NMTOKENS"/>
+      <xs:attribute name="modifiers" type="xs:NMTOKENS"/>
     </xs:complexType>
   </xs:element>
   
diff --git a/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-missing.xml b/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-missing.xml
index dad045e1e46..cc7f090ca65 100644
--- a/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-missing.xml
+++ b/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-missing.xml
@@ -45,7 +45,7 @@
     </keys>
 
     <layers formId="iso">
-        <layer modifier="none">
+        <layer modifiers="none">
             <row keys="c-tikka 1 2 3 4 5 6 7 8 9 0 minus equals" />
             <row keys="q w e r t y u i o p g-tikka h-maqtua" />
             <row keys="a s d f g h j k l semi-colon hash" />
@@ -53,7 +53,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="shift">
+        <layer modifiers="shift">
             <row keys="C-tikka bang double-quote euro dollar percent caret amp open-paren close-paren underscore plus" />
             <row keys="Q W E R T Y U I O P G-tikka H-maqtua" />
             <row keys="A S D F G H J K L colon at tilde" />
@@ -61,7 +61,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR">
+        <layer modifiers="altR">
             <row keys="grave gap gap pound gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap e-grave gap gap gap u-grave i-grave o-grave gap open-square close-square" />
             <row keys="a-grave gap gap gap gap gap gap gap gap gap gap gap" />
@@ -69,7 +69,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR-shift">
+        <layer modifiers="altR-shift">
             <row keys="not gap gap gap gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap E-grave gap gap gap U-grave I-grave O-grave gap open-curly close-curly" />
             <row keys="A-grave gap gap gap gap gap gap gap gap gap gap gap" />
diff --git a/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-unknownbase.xml b/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-unknownbase.xml
index a7fe30b2763..d263e22d1e9 100644
--- a/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-unknownbase.xml
+++ b/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-unknownbase.xml
@@ -45,7 +45,7 @@
     </keys>
 
     <layers formId="iso">
-        <layer modifier="none">
+        <layer modifiers="none">
             <row keys="c-tikka 1 2 3 4 5 6 7 8 9 0 minus equals" />
             <row keys="q w e r t y u i o p g-tikka h-maqtua" />
             <row keys="a s d f g h j k l semi-colon hash" />
@@ -53,7 +53,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="shift">
+        <layer modifiers="shift">
             <row keys="C-tikka bang double-quote euro dollar percent caret amp open-paren close-paren underscore plus" />
             <row keys="Q W E R T Y U I O P G-tikka H-maqtua" />
             <row keys="A S D F G H J K L colon at tilde" />
@@ -61,7 +61,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR">
+        <layer modifiers="altR">
             <row keys="grave gap gap pound gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap e-grave gap gap gap u-grave i-grave o-grave gap open-square close-square" />
             <row keys="a-grave gap gap gap gap gap gap gap gap gap gap gap" />
@@ -69,7 +69,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR-shift">
+        <layer modifiers="altR-shift">
             <row keys="not gap gap gap gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap E-grave gap gap gap U-grave I-grave O-grave gap open-curly close-curly" />
             <row keys="A-grave gap gap gap gap gap gap gap gap gap gap gap" />
diff --git a/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-unknownver.xml b/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-unknownver.xml
index f1443c3eb02..f53328cde5b 100644
--- a/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-unknownver.xml
+++ b/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-unknownver.xml
@@ -47,7 +47,7 @@
     </keys>
 
     <layers formId="iso">
-        <layer modifier="none">
+        <layer modifiers="none">
             <row keys="c-tikka 1 2 3 4 5 6 7 8 9 0 minus equals" />
             <row keys="q w e r t y u i o p g-tikka h-maqtua" />
             <row keys="a s d f g h j k l semi-colon hash" />
@@ -55,7 +55,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="shift">
+        <layer modifiers="shift">
             <row keys="C-tikka bang double-quote euro dollar percent caret amp open-paren close-paren underscore plus" />
             <row keys="Q W E R T Y U I O P G-tikka H-maqtua" />
             <row keys="A S D F G H J K L colon at tilde" />
@@ -63,7 +63,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR">
+        <layer modifiers="altR">
             <row keys="grave gap gap pound gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap e-grave gap gap gap u-grave i-grave o-grave gap open-square close-square" />
             <row keys="a-grave gap gap gap gap gap gap gap gap gap gap gap" />
@@ -71,7 +71,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR-shift">
+        <layer modifiers="altR-shift">
             <row keys="not gap gap gap gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap E-grave gap gap gap U-grave I-grave O-grave gap open-curly close-curly" />
             <row keys="A-grave gap gap gap gap gap gap gap gap gap gap gap" />
diff --git a/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-wrongparent.xml b/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-wrongparent.xml
index de14815c45a..f6a56784e87 100644
--- a/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-wrongparent.xml
+++ b/tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-wrongparent.xml
@@ -45,7 +45,7 @@
     </keys>
 
     <layers formId="iso">
-        <layer modifier="none">
+        <layer modifiers="none">
             <row keys="c-tikka 1 2 3 4 5 6 7 8 9 0 minus equals" />
             <row keys="q w e r t y u i o p g-tikka h-maqtua" />
             <row keys="a s d f g h j k l semi-colon hash" />
@@ -53,7 +53,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="shift">
+        <layer modifiers="shift">
             <row keys="C-tikka bang double-quote euro dollar percent caret amp open-paren close-paren underscore plus" />
             <row keys="Q W E R T Y U I O P G-tikka H-maqtua" />
             <row keys="A S D F G H J K L colon at tilde" />
@@ -61,7 +61,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR">
+        <layer modifiers="altR">
             <row keys="grave gap gap pound gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap e-grave gap gap gap u-grave i-grave o-grave gap open-square close-square" />
             <row keys="a-grave gap gap gap gap gap gap gap gap gap gap gap" />
@@ -69,7 +69,7 @@
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR-shift">
+        <layer modifiers="altR-shift">
             <row keys="not gap gap gap gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap E-grave gap gap gap U-grave I-grave O-grave gap open-curly close-curly" />
             <row keys="A-grave gap gap gap gap gap gap gap gap gap gap gap" />