diff --git a/doc/xmllint.xml b/doc/xmllint.xml
index 4def2b1a..b6fcae90 100644
--- a/doc/xmllint.xml
+++ b/doc/xmllint.xml
@@ -585,7 +585,10 @@
         <varlistentry>
             <term><option>--insert</option></term>
             <listitem>
-                <para>Test for valid insertions.</para>
+                <para>
+                    Test for valid insertions. DEPRECATED: This feature
+                    will be removed.
+                </para>
             </listitem>
         </varlistentry>
 
diff --git a/include/libxml/valid.h b/include/libxml/valid.h
index e2538e0a..b7d38a6e 100644
--- a/include/libxml/valid.h
+++ b/include/libxml/valid.h
@@ -372,6 +372,7 @@ XMLPUBFUN int
 					 const xmlChar *notationName);
 #endif /* LIBXML_VALID_ENABLED */
 
+XML_DEPRECATED
 XMLPUBFUN int
 		xmlIsMixedElement	(xmlDoc *doc,
 					 const xmlChar *name);
@@ -397,12 +398,14 @@ XMLPUBFUN xmlElement *
 
 #ifdef LIBXML_VALID_ENABLED
 
+XML_DEPRECATED
 XMLPUBFUN int
 		xmlValidGetPotentialChildren(xmlElementContent *ctree,
 					 const xmlChar **names,
 					 int *len,
 					 int max);
 
+/* only needed for `xmllint --insert` */
 XMLPUBFUN int
 		xmlValidGetValidElements(xmlNode *prev,
 					 xmlNode *next,
diff --git a/python/generator.py b/python/generator.py
index 05e22062..1d394b39 100755
--- a/python/generator.py
+++ b/python/generator.py
@@ -605,6 +605,7 @@ deprecated_funcs = {
     'xmlIsExtender': True,
     'xmlIsIdeographic': True,
     'xmlIsLetter': True,
+    'xmlIsMixedElement': True,
     'xmlIsPubidChar': True,
     'xmlIsRef': True,
     'xmlKeepBlanksDefault': True,
diff --git a/valid.c b/valid.c
index f5faa369..a6b0783f 100644
--- a/valid.c
+++ b/valid.c
@@ -3020,6 +3020,8 @@ xmlValidateNotationUse(xmlValidCtxt *ctxt, xmlDoc *doc,
  * Search in the DTDs whether an element accepts mixed content
  * or ANY (basically if it is supposed to accept text children).
  *
+ * @deprecated Internal function, don't use.
+ *
  * @param doc  the document
  * @param name  the element name
  * @returns 0 if no, 1 if yes, and -1 if no element description
@@ -6375,6 +6377,8 @@ xmlCtxtValidateDocument(xmlParserCtxt *ctxt, xmlDoc *doc) {
 /**
  * Build/extend a list of  potential children allowed by the content tree
  *
+ * @deprecated Internal function, don't use.
+ *
  * @param ctree  an element content tree
  * @param names  an array to store the list of child names
  * @param len  a pointer to the number of element in the list
@@ -6437,6 +6441,8 @@ static void xmlNoValidityErr(void *ctx ATTRIBUTE_UNUSED,
  * pointers to the element names are inserted at the beginning of the array
  * and do not need to be freed.
  *
+ * @deprecated This feature will be removed.
+ *
  * @param prev  an element to insert after
  * @param next  an element to insert next
  * @param names  an array to store the list of child names