Mark underscored properties as internal

These properties look like they were intended to be internal but they were missing the `PROPERTY_USAGE_INTERNAL` flag.

- `PackedScene::_bundled`
- `PortableCompressedTexture2D::_data`
- `ImporterMesh::_data`

doc/classes/ImporterMesh.xml

@@ -191,8 +191,4 @@
 			</description>
 		</method>
 	</methods>
-	<members>
-		<member name="_data" type="Dictionary" setter="_set_data" getter="_get_data" default="{ &quot;surfaces&quot;: [] }">
-		</member>
-	</members>
 </class>

doc/classes/PackedScene.xml

@@ -103,12 +103,6 @@
 			</description>
 		</method>
 	</methods>
-	<members>
-		<member name="_bundled" type="Dictionary" setter="_set_bundled_scene" getter="_get_bundled_scene" default="{ &quot;conn_count&quot;: 0, &quot;conns&quot;: PackedInt32Array(), &quot;editable_instances&quot;: [], &quot;names&quot;: PackedStringArray(), &quot;node_count&quot;: 0, &quot;node_paths&quot;: [], &quot;nodes&quot;: PackedInt32Array(), &quot;variants&quot;: [], &quot;version&quot;: 3 }">
-			A dictionary representation of the scene contents.
-			Available keys include "names" and "variants" for resources, "node_count", "nodes", "node_paths" for nodes, "editable_instances" for paths to overridden nodes, "conn_count" and "conns" for signal connections, and "version" for the format style of the PackedScene.
-		</member>
-	</members>
 	<constants>
 		<constant name="GEN_EDIT_STATE_DISABLED" value="0" enum="GenEditState">
 			If passed to [method instantiate], blocks edits to the scene state.

doc/classes/PortableCompressedTexture2D.xml

@@ -52,8 +52,6 @@
 		</method>
 	</methods>
 	<members>
-		<member name="_data" type="PackedByteArray" setter="_set_data" getter="_get_data" default="PackedByteArray()">
-		</member>
 		<member name="keep_compressed_buffer" type="bool" setter="set_keep_compressed_buffer" getter="is_keeping_compressed_buffer" default="false">
 			When running on the editor, this class will keep the source compressed data in memory. Otherwise, the source compressed data is lost after loading and the resource can't be re saved.
 			This flag allows to keep the compressed data in memory if you intend it to persist after loading.

scene/resources/3d/importer_mesh.cpp

@@ -1377,5 +1377,5 @@ void ImporterMesh::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_lightmap_size_hint", "size"), &ImporterMesh::set_lightmap_size_hint);
 	ClassDB::bind_method(D_METHOD("get_lightmap_size_hint"), &ImporterMesh::get_lightmap_size_hint);
 
-	ADD_PROPERTY(PropertyInfo(Variant::DICTIONARY, "_data", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR), "_set_data", "_get_data");
+	ADD_PROPERTY(PropertyInfo(Variant::DICTIONARY, "_data", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL), "_set_data", "_get_data");
 }

scene/resources/packed_scene.cpp

@@ -2199,7 +2199,7 @@ void PackedScene::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("_get_bundled_scene"), &PackedScene::_get_bundled_scene);
 	ClassDB::bind_method(D_METHOD("get_state"), &PackedScene::get_state);
 
-	ADD_PROPERTY(PropertyInfo(Variant::DICTIONARY, "_bundled"), "_set_bundled_scene", "_get_bundled_scene");
+	ADD_PROPERTY(PropertyInfo(Variant::DICTIONARY, "_bundled", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_INTERNAL), "_set_bundled_scene", "_get_bundled_scene");
 
 	BIND_ENUM_CONSTANT(GEN_EDIT_STATE_DISABLED);
 	BIND_ENUM_CONSTANT(GEN_EDIT_STATE_INSTANCE);

scene/resources/portable_compressed_texture.cpp

@@ -345,7 +345,7 @@ void PortableCompressedTexture2D::_bind_methods() {
 	ClassDB::bind_static_method("PortableCompressedTexture2D", D_METHOD("set_keep_all_compressed_buffers", "keep"), &PortableCompressedTexture2D::set_keep_all_compressed_buffers);
 	ClassDB::bind_static_method("PortableCompressedTexture2D", D_METHOD("is_keeping_all_compressed_buffers"), &PortableCompressedTexture2D::is_keeping_all_compressed_buffers);
 
-	ADD_PROPERTY(PropertyInfo(Variant::PACKED_BYTE_ARRAY, "_data", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR), "_set_data", "_get_data");
+	ADD_PROPERTY(PropertyInfo(Variant::PACKED_BYTE_ARRAY, "_data", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL), "_set_data", "_get_data");
 	ADD_PROPERTY(PropertyInfo(Variant::VECTOR2, "size_override", PROPERTY_HINT_NONE, "suffix:px"), "set_size_override", "get_size_override");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "keep_compressed_buffer"), "set_keep_compressed_buffer", "is_keeping_compressed_buffer");