diff --git a/importlib_metadata/_adapters.py b/importlib_metadata/_adapters.py
index 0bc23000..3c5a7db9 100644
--- a/importlib_metadata/_adapters.py
+++ b/importlib_metadata/_adapters.py
@@ -59,6 +59,9 @@ class Message(email.message.Message):
             FoldedCase,
             [
                 'Classifier',
+                'Import-Name',
+                'Import-Namespace',
+                'License-File',
                 'Obsoletes-Dist',
                 'Platform',
                 'Project-URL',
@@ -72,7 +75,7 @@ class Message(email.message.Message):
         )
     )
     """
-    Keys that may be indicated multiple times per PEP 566.
+    Keys that may be indicated multiple times in Core Metadata.
     """
 
     def __new__(cls, orig: email.message.Message):
diff --git a/newsfragments/+json-multiple-use.bugfix.rst b/newsfragments/+json-multiple-use.bugfix.rst
new file mode 100644
index 00000000..cad1ea4a
--- /dev/null
+++ b/newsfragments/+json-multiple-use.bugfix.rst
@@ -0,0 +1 @@
+Return ``License-File``, ``Import-Name``, and ``Import-Namespace`` as lists in JSON-compatible metadata, including when only one value is present, and retain all repeated values as required by PEP 566.