Apple watches most commonly use a generic watchOS version.

Tests/fixtures/wearable.yml

@@ -287,6 +287,20 @@
     model: Watch Series 5 44mm
   os_family: iOS
   browser_family: Unknown
+-
+  user_agent: atc/1.0 watchOS
+  os:
+    name: watchOS
+    version: ""
+    platform: ARM
+  client: null
+  device:
+    type: wearable
+    brand: Apple
+    model: Watch
+  os_family: iOS
+  browser_family: Unknown
+
 -
   user_agent: com.apple.appstored/1.0 watchOS/7.0 model/Watch6,1 hwp/t8301 build/18R382 (6; dt:226) AMS/1
   os:

regexes/device/mobiles.yml

@@ -1006,7 +1006,7 @@ Apple:
     - regex: 'Watch7,[24]'
       device: 'wearable'
       model: 'Watch Series 9 45mm'
-    - regex: 'Apple Watch'
+    - regex: '(:?Apple Watch|watchOS)'
       device: 'wearable'
       model: 'Watch'
 

regexes/oss.yml

@@ -1200,7 +1200,7 @@
 ##########
 # watchOS (https://developer.apple.com/watchos/)
 ##########
-- regex: '(?:Watch1,[12]/|Watch OS,|watchOS[ /])(\d+[\.\d]*)'
+- regex: '(?:Watch1,[12]/|Watch OS,|watchOS[ /]?)(\d+[\.\d]*)?'
   name: 'watchOS'
   version: '$1'
 - regex: 'Apple Watch(?!;)'