diff --git a/.github/workflows/analyzers.yaml b/.github/workflows/analyzers.yaml
index 7ade8b20..3735eeae 100644
--- a/.github/workflows/analyzers.yaml
+++ b/.github/workflows/analyzers.yaml
@@ -13,6 +13,7 @@ jobs:
             matrix:
                 operating-system: [ubuntu-latest]
                 php-versions: ['8.4']
+                composer-options: ['--ignore-platform-req=php+']
             fail-fast: false
         name: PHP ${{ matrix.php-versions }} @ ${{ matrix.operating-system }}
         steps:
diff --git a/.github/workflows/autoloader.yaml b/.github/workflows/autoloader.yaml
index 39e7ec94..db62f8fa 100644
--- a/.github/workflows/autoloader.yaml
+++ b/.github/workflows/autoloader.yaml
@@ -8,6 +8,7 @@ jobs:
             matrix:
                 operating-system: [ubuntu-latest]
                 php-versions: ['8.4']
+                composer-options: ['--ignore-platform-req=php+']
             fail-fast: false
         name: PHP ${{ matrix.php-versions }} @ ${{ matrix.operating-system }}
         steps:
diff --git a/.github/workflows/code-style.yaml b/.github/workflows/code-style.yaml
index dadf1e6c..f2ea74db 100644
--- a/.github/workflows/code-style.yaml
+++ b/.github/workflows/code-style.yaml
@@ -12,6 +12,7 @@ jobs:
             matrix:
                 operating-system: [ubuntu-latest]
                 php-versions: ['8.4']
+                composer-options: ['--ignore-platform-req=php+']
             fail-fast: false
         name: PHP ${{ matrix.php-versions }} @ ${{ matrix.operating-system }}
         steps:
diff --git a/.github/workflows/stress.yaml b/.github/workflows/stress.yaml
index 4141f4f2..82ebbdf1 100644
--- a/.github/workflows/stress.yaml
+++ b/.github/workflows/stress.yaml
@@ -8,6 +8,7 @@ jobs:
             matrix:
                 operating-system: [ubuntu-latest]
                 php-versions: ['8.4']
+                composer-options: ['--ignore-platform-req=php+']
             fail-fast: false
         name: PHP ${{ matrix.php-versions }} @ ${{ matrix.operating-system }}
         steps:
diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 013c038a..65df9e7e 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -13,7 +13,7 @@ jobs:
             matrix:
                 operating-system: [ubuntu-latest]
                 php-versions: ['8.4']
-                experimental: [false]
+                composer-options: ['--ignore-platform-req=php+']
             fail-fast: false
         name: PHP ${{ matrix.php-versions }} @ ${{ matrix.operating-system }}
         steps:
diff --git a/psalm.xml b/psalm.xml
index 95604c82..8cf94053 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -45,6 +45,7 @@
     </issueHandlers>
     <stubs>
         <file name="stubs/DOM.phpstub" />
+        <file name="stubs/php_xsl.stub.phpstub" />
         <file name="stubs/XMLReader.phpstub" />
         <file name="stubs/XMLWriter.phpstub" />
     </stubs>
diff --git a/src/Xml/Dom/Collection/NodeList.php b/src/Xml/Dom/Collection/NodeList.php
index fa8191e1..a78ddc12 100644
--- a/src/Xml/Dom/Collection/NodeList.php
+++ b/src/Xml/Dom/Collection/NodeList.php
@@ -8,7 +8,7 @@
 use \DOM\Element;
 use \DOM\Node;
 use \DOM\NodeList as DOMNodeList;
-use DOMXpath as DOMXpath;
+use \DOM\XPath as DOMXPath;
 use Generator;
 use InvalidArgumentException;
 use IteratorAggregate;
@@ -193,7 +193,7 @@ public function reduce(callable $reducer, mixed $initial): mixed
     }
 
     /**
-     * @param list<callable(DOMXpath): DOMXpath> $configurators
+     * @param list<callable(DOMXPath): DOMXPath> $configurators
      * @throws RuntimeException
      * @return NodeList<\DOM\Node>
      */
@@ -211,7 +211,7 @@ public function query(string $xpath, callable ... $configurators): self
 
     /**
      * @template X
-     * @param list<callable(DOMXpath): DOMXpath> $configurators
+     * @param list<callable(DOMXPath): DOMXPath> $configurators
      * @param TypeInterface<X> $type
      * @return list<X>
      */
diff --git a/src/Xml/Dom/Locator/Node/detect_document.php b/src/Xml/Dom/Locator/Node/detect_document.php
index 86a5c7a5..d3a31888 100644
--- a/src/Xml/Dom/Locator/Node/detect_document.php
+++ b/src/Xml/Dom/Locator/Node/detect_document.php
@@ -5,16 +5,14 @@
 namespace VeeWee\Xml\Dom\Locator\Node;
 
 use \DOM\XMLDocument;
-use \DOM\Node;
 use InvalidArgumentException;
-use Webmozart\Assert\Assert;
+use function VeeWee\Xml\Dom\Assert\assert_document;
 use function VeeWee\Xml\Dom\Predicate\is_document;
 
 /**
  * @throws InvalidArgumentException
- * @psalm-suppress RedundantCondition - node->ownerDocument can also be null...
  */
 function detect_document(\DOM\Node $node): \DOM\XMLDocument
 {
-    return is_document($node) ? $node : $node->ownerDocument;
+    return is_document($node) ? $node : assert_document($node->ownerDocument);
 }
diff --git a/src/Xml/Dom/Locator/Xsd/locate_namespaced_xsd_schemas.php b/src/Xml/Dom/Locator/Xsd/locate_namespaced_xsd_schemas.php
index 47d45e4f..e4b2ffeb 100644
--- a/src/Xml/Dom/Locator/Xsd/locate_namespaced_xsd_schemas.php
+++ b/src/Xml/Dom/Locator/Xsd/locate_namespaced_xsd_schemas.php
@@ -10,6 +10,7 @@
 use VeeWee\Xml\Xsd\Schema\Schema;
 use VeeWee\Xml\Xsd\Schema\SchemaCollection;
 use function Psl\Regex\split;
+use function VeeWee\Xml\Dom\Locator\document_element;
 
 /**
  * @throws RuntimeException
@@ -17,15 +18,15 @@
 function locate_namespaced_xsd_schemas(\DOM\XMLDocument $document): SchemaCollection
 {
     $schemaNs = Xmlns::xsi()->value();
-    $attributes = $document->documentElement->attributes;
+    $documentElement = document_element()($document);
+    $attributes = $documentElement->attributes;
     $collection = new SchemaCollection();
 
     if (!$schemaLocation = $attributes->getNamedItemNS($schemaNs, 'schemaLocation')) {
         return $collection;
     }
 
-    /** @psalm-suppress MissingThrowsDocblock - Covered the runtime exception! */
-    $parts = split(trim($schemaLocation->textContent), '/\s+/');
+    $parts = split(trim($schemaLocation->textContent ?? ''), '/\s+/');
     $partsCount = count($parts);
     for ($k = 0; $k < $partsCount; $k += 2) {
         $collection = $collection->add(Schema::withNamespace($parts[$k], $parts[$k + 1]));
diff --git a/src/Xml/Dom/Locator/Xsd/locate_no_namespaced_xsd_schemas.php b/src/Xml/Dom/Locator/Xsd/locate_no_namespaced_xsd_schemas.php
index 2a9600f0..b03abf50 100644
--- a/src/Xml/Dom/Locator/Xsd/locate_no_namespaced_xsd_schemas.php
+++ b/src/Xml/Dom/Locator/Xsd/locate_no_namespaced_xsd_schemas.php
@@ -11,6 +11,7 @@
 use VeeWee\Xml\Xsd\Schema\SchemaCollection;
 use function Psl\Dict\map;
 use function Psl\Regex\split;
+use function VeeWee\Xml\Dom\Locator\document_element;
 
 /**
  * @throws RuntimeException
@@ -18,13 +19,13 @@
 function locate_no_namespaced_xsd_schemas(\DOM\XMLDocument $document): SchemaCollection
 {
     $schemaNs = Xmlns::xsi()->value();
-    $attributes = $document->documentElement->attributes;
+    $documentElement = document_element()($document);
+    $attributes = $documentElement->attributes;
     if (!$schemaLocNoNamespace = $attributes->getNamedItemNS($schemaNs, 'noNamespaceSchemaLocation')) {
         return new SchemaCollection();
     }
 
-    /** @psalm-suppress MissingThrowsDocblock - Covered the runtime exception! */
-    $parts = split(trim($schemaLocNoNamespace->textContent), '/\s+/');
+    $parts = split(trim($schemaLocNoNamespace->textContent ?? ''), '/\s+/');
 
     return new SchemaCollection(
         ...map(
diff --git a/src/Xml/Dom/Locator/document_element.php b/src/Xml/Dom/Locator/document_element.php
index 821b9976..ace573b3 100644
--- a/src/Xml/Dom/Locator/document_element.php
+++ b/src/Xml/Dom/Locator/document_element.php
@@ -7,11 +7,12 @@
 use Closure;
 use \DOM\XMLDocument;
 use \DOM\Element;
+use function VeeWee\Xml\Dom\Assert\assert_element;
 
 /**
  * @return Closure(\DOM\XMLDocument): \DOM\Element
  */
 function document_element(): Closure
 {
-    return static fn (\DOM\XMLDocument $document): \DOM\Element => $document->documentElement;
+    return static fn (\DOM\XMLDocument $document): \DOM\Element => assert_element($document->documentElement);
 }
diff --git a/src/Xml/Dom/Locator/elements_with_namespaced_tagname.php b/src/Xml/Dom/Locator/elements_with_namespaced_tagname.php
index 951f9a7b..eefbf3e5 100644
--- a/src/Xml/Dom/Locator/elements_with_namespaced_tagname.php
+++ b/src/Xml/Dom/Locator/elements_with_namespaced_tagname.php
@@ -20,5 +20,9 @@ function elements_with_namespaced_tagname(string $namespace, string $localTagNam
          * @return NodeList<\DOM\Element>
          */
         static fn (\DOM\XMLDocument $document): NodeList
-            => locate_by_namespaced_tag_name($document->documentElement, $namespace, $localTagName);
+            => locate_by_namespaced_tag_name(
+                document_element()($document),
+                $namespace,
+                $localTagName
+            );
 }
diff --git a/src/Xml/Dom/Locator/elements_with_tagname.php b/src/Xml/Dom/Locator/elements_with_tagname.php
index c2773fbb..6159b731 100644
--- a/src/Xml/Dom/Locator/elements_with_tagname.php
+++ b/src/Xml/Dom/Locator/elements_with_tagname.php
@@ -20,5 +20,8 @@ function elements_with_tagname(string $tagName): Closure
          * @return NodeList<\DOM\Element>
          */
         static fn (\DOM\XMLDocument $document): NodeList
-            => locate_by_tag_name($document->documentElement, $tagName);
+            => locate_by_tag_name(
+                document_element()($document),
+                $tagName
+            );
 }
diff --git a/src/Xml/Dom/Locator/root_namespace.php b/src/Xml/Dom/Locator/root_namespace.php
index d182f0ad..719c6bbf 100644
--- a/src/Xml/Dom/Locator/root_namespace.php
+++ b/src/Xml/Dom/Locator/root_namespace.php
@@ -12,5 +12,5 @@
  */
 function root_namespace_uri(): Closure
 {
-    return static fn (\DOM\XMLDocument $document): ?string => $document->documentElement->namespaceURI;
+    return static fn (\DOM\XMLDocument $document): ?string => document_element()($document)->namespaceURI;
 }
diff --git a/src/Xml/Dom/Manipulator/Attribute/rename.php b/src/Xml/Dom/Manipulator/Attribute/rename.php
index e3b2ea73..cac7cbd0 100644
--- a/src/Xml/Dom/Manipulator/Attribute/rename.php
+++ b/src/Xml/Dom/Manipulator/Attribute/rename.php
@@ -18,6 +18,9 @@ function rename(\DOM\Attr $target, string $newQName, ?string $newNamespaceURI =
 {
     return disallow_issues(static fn (): \DOM\Attr => match(true) {
         is_xmlns_attribute($target) => rename_xmlns_attribute($target, $newQName),
-        default => tap(fn () => $target->rename($newNamespaceURI, $newQName))($target)
+        default => (function() use ($target, $newNamespaceURI, $newQName): \DOM\Attr {
+            $target->rename($newNamespaceURI, $newQName);
+            return $target;
+        })()
     });
 }
diff --git a/src/Xml/Dom/Manipulator/Document/optimize_namespaces.php b/src/Xml/Dom/Manipulator/Document/optimize_namespaces.php
index 1f351f2c..0f1a95e8 100644
--- a/src/Xml/Dom/Manipulator/Document/optimize_namespaces.php
+++ b/src/Xml/Dom/Manipulator/Document/optimize_namespaces.php
@@ -10,6 +10,7 @@
 use function Psl\Vec\sort;
 use function Psl\Vec\values;
 use function VeeWee\Xml\Dom\Builder\xmlns_attribute;
+use function VeeWee\Xml\Dom\Locator\document_element;
 use function VeeWee\Xml\Dom\Locator\Xmlns\recursive_linked_namespaces;
 use function VeeWee\Xml\Dom\Manipulator\Xmlns\rename_element_namespace;
 
@@ -18,10 +19,10 @@
  */
 function optimize_namespaces(\DOM\XMLDocument $document, string $prefix = 'ns'): void
 {
-    $documentElement = $document->documentElement;
+    $documentElement = document_element()($document);
     $namespaceURIs = values(unique(map(
         recursive_linked_namespaces($documentElement),
-        static fn (\DOM\NamespaceInfo $info): string => $info->namespaceURI
+        static fn (\DOM\NamespaceInfo $info): string => $info->namespaceURI ?? ''
     )));
 
     foreach (sort($namespaceURIs) as $index => $namespaceURI) {
diff --git a/src/Xml/Dom/Manipulator/Element/copy_named_xmlns_attributes.php b/src/Xml/Dom/Manipulator/Element/copy_named_xmlns_attributes.php
index b2a32f7c..9eb8136e 100644
--- a/src/Xml/Dom/Manipulator/Element/copy_named_xmlns_attributes.php
+++ b/src/Xml/Dom/Manipulator/Element/copy_named_xmlns_attributes.php
@@ -14,7 +14,7 @@
 function copy_named_xmlns_attributes(\DOM\Element $target, \DOM\Element $source): void
 {
     xmlns_attributes_list($source)->forEach(static function (\DOM\Attr $xmlns) use ($target) {
-        if ($xmlns->prefix && !$target->hasAttribute($xmlns->nodeName)) {
+        if ($xmlns->prefix !== null && !$target->hasAttribute($xmlns->nodeName)) {
             xmlns_attribute($xmlns->localName, $xmlns->value)($target);
         }
     });
diff --git a/src/Xml/Dom/Manipulator/Element/rename.php b/src/Xml/Dom/Manipulator/Element/rename.php
index 58b4affa..b220cd3d 100644
--- a/src/Xml/Dom/Manipulator/Element/rename.php
+++ b/src/Xml/Dom/Manipulator/Element/rename.php
@@ -16,7 +16,7 @@ function rename(\DOM\Element $target, string $newQName, ?string $newNamespaceURI
     $newPrefix = $parts[0] ?? '';
 
     /*
-     * To make sure the new namespace prefix is being used, we need to apply an additional xmlns declaration chech:
+     * To make sure the new namespace prefix is being used, we need to apply an additional xmlns declaration check:
      * This is due to a particular rule in the XML serialization spec,
      * that enforces that a namespaceURI on an element is only associated with exactly one prefix.
      * See the note of bullet point 2 of https://www.w3.org/TR/DOM-Parsing/#dfn-concept-serialize-xml.
@@ -24,7 +24,7 @@ function rename(\DOM\Element $target, string $newQName, ?string $newNamespaceURI
      * If you rename a:xx to b:xx an xmlns:b="xx" attribute gets added at the end, but prefix a: will still be serialized.
      * So in this case, we need to remove the xmlns declaration first.
      */
-    if ($newPrefix && $newPrefix !== $target->prefix && $target->hasAttribute('xmlns:'.$target->prefix)) {
+    if ($newPrefix && $target->prefix !== null && $newPrefix !== $target->prefix && $target->hasAttribute('xmlns:'.$target->prefix)) {
         $target->removeAttribute('xmlns:'.$target->prefix);
     }
 
diff --git a/src/Xml/Dom/Traverser/Visitor/RemoveNamespaces.php b/src/Xml/Dom/Traverser/Visitor/RemoveNamespaces.php
index 0da7c9a9..adfd2b6a 100644
--- a/src/Xml/Dom/Traverser/Visitor/RemoveNamespaces.php
+++ b/src/Xml/Dom/Traverser/Visitor/RemoveNamespaces.php
@@ -18,7 +18,7 @@ final class RemoveNamespaces extends AbstractVisitor
     private $filter;
 
     /**
-     * @param null | callable(\DOM\Attr): bool $filter
+     * @param null | callable(\DOM\Attr | \DOM\Element): bool $filter
      */
     public function __construct(
         ?callable $filter = null
@@ -81,6 +81,7 @@ public function onNodeEnter(\DOM\Node $node): Action
             return new Action\Noop();
         }
 
+        /** @var \DOM\Element | \DOM\Attr $node */
         return new Action\RenameNode($node->localName, null);
     }
 
diff --git a/src/Xml/Encoding/Internal/Decoder/Builder/element.php b/src/Xml/Encoding/Internal/Decoder/Builder/element.php
index d9bf9913..c79047c6 100644
--- a/src/Xml/Encoding/Internal/Decoder/Builder/element.php
+++ b/src/Xml/Encoding/Internal/Decoder/Builder/element.php
@@ -22,7 +22,7 @@ function element(\DOM\Element $element): array
     $namespaces = namespaces($element);
 
     if (!count($children) && !count($attributes) && !count($namespaces)) {
-        return [$name => $element->textContent];
+        return [$name => $element->textContent ?? ''];
     }
 
     return [
@@ -30,7 +30,7 @@ function element(\DOM\Element $element): array
             merge(
                 $namespaces,
                 $attributes,
-                $children ?: ['@value' => $element->textContent]
+                $children ?: ['@value' => $element->textContent ?? '']
             ),
             static fn (mixed $data): bool => $data !== []
         )
diff --git a/src/Xml/Encoding/Internal/Decoder/Builder/namespaces.php b/src/Xml/Encoding/Internal/Decoder/Builder/namespaces.php
index ddf5a5a4..05232afb 100644
--- a/src/Xml/Encoding/Internal/Decoder/Builder/namespaces.php
+++ b/src/Xml/Encoding/Internal/Decoder/Builder/namespaces.php
@@ -22,7 +22,7 @@ function namespaces(\DOM\Element $element): array
             static fn (array $namespaces, \DOM\Attr $node)
                 => $node->value
                     ? merge($namespaces, [
-                        ($node->prefix ? $node->localName : '') => $node->value
+                        ($node->prefix !== null ? $node->localName : '') => $node->value
                     ])
                     : $namespaces,
             []
diff --git a/stubs/DOM.phpstub b/stubs/DOM.phpstub
index 80923b09..1208b349 100644
--- a/stubs/DOM.phpstub
+++ b/stubs/DOM.phpstub
@@ -1027,6 +1027,9 @@ namespace
 
 namespace DOM
 {
+
+    use Psl\Iter\Iterator;
+
     /**
      * @var int
      * @cvalue INDEX_SIZE_ERR
@@ -1163,7 +1166,10 @@ namespace DOM
         public ?Element $parentElement;
         /** @implementation-alias DOMNode::hasChildNodes */
         public function hasChildNodes(): bool {}
-        /** @readonly */
+        /**
+         * @readonly
+         * @var NodeList<Node>
+         */
         public NodeList $childNodes;
         /** @readonly */
         public ?Node $firstChild;
@@ -1218,7 +1224,11 @@ namespace DOM
         public function __wakeup(): void {}
     }
 
-    class NodeList implements IteratorAggregate, Countable
+    /**
+     * @template-covariant TNode as \DOM\Node
+     * @template-implements \IteratorAggregate<int, TNode>
+     */
+    class NodeList implements \IteratorAggregate, \Countable
     {
         /** @readonly */
         public int $length;
@@ -1226,14 +1236,23 @@ namespace DOM
         /** @implementation-alias DOMNodeList::count */
         public function count(): int {}
 
-        /** @implementation-alias DOMNodeList::getIterator */
+        /**
+         * @implementation-alias DOMNodeList::getIterator
+         * @psalm-return iterable<int, TNode>
+         */
         public function getIterator(): \Iterator {}
 
-        /** @implementation-alias DOMNodeList::item */
+        /**
+         * @implementation-alias DOMNodeList::item
+         * @psalm-return TNode
+         */
         public function item(int $index): ?Node {}
     }
 
-    class NamedNodeMap implements IteratorAggregate, Countable
+    /**
+     * @implements \IteratorAggregate<array-key, \DOM\Attr>
+     */
+    class NamedNodeMap implements \IteratorAggregate, \Countable
     {
         /** @readonly */
         public int $length;
@@ -1248,11 +1267,14 @@ namespace DOM
         /** @implementation-alias DOMNamedNodeMap::count */
         public function count(): int {}
 
-        /** @implementation-alias DOMNamedNodeMap::getIterator */
+        /**
+         * @implementation-alias DOMNamedNodeMap::getIterator
+         * @psalm-return iterable<array-key, \DOM\Attr>
+         */
         public function getIterator(): \Iterator {}
     }
 
-    class DTDNamedNodeMap implements IteratorAggregate, Countable
+    class DTDNamedNodeMap implements \IteratorAggregate, \Countable
     {
         /** @readonly */
         public int $length;
@@ -1271,7 +1293,10 @@ namespace DOM
         public function getIterator(): \Iterator {}
     }
 
-    class HTMLCollection implements IteratorAggregate, Countable
+    /**
+     * @implements \IteratorAggregate<array-key, \DOM\Element>
+     */
+    class HTMLCollection implements \IteratorAggregate, \Countable
     {
         /** @readonly */
         public int $length;
@@ -1284,7 +1309,10 @@ namespace DOM
         /** @implementation-alias DOMNodeList::count */
         public function count(): int {}
 
-        /** @implementation-alias DOMNodeList::getIterator */
+        /**
+         * @implementation-alias DOMNodeList::getIterator
+         * @psalm-return iterable<array-key, \DOM\Element>
+         */
         public function getIterator(): \Iterator {}
     }
 
@@ -1528,9 +1556,7 @@ namespace DOM
     {
         /** @readonly */
         public Implementation $implementation;
-        /** @readonly */
         public string $URL;
-        /** @readonly */
         public string $documentURI;
         public string $characterSet;
         public string $charset;
diff --git a/stubs/php_xsl.stub.phpstub b/stubs/php_xsl.stub.phpstub
new file mode 100644
index 00000000..c01e2181
--- /dev/null
+++ b/stubs/php_xsl.stub.phpstub
@@ -0,0 +1,131 @@
+<?php
+
+/** @generate-class-entries */
+
+/** @var int */
+const XSL_CLONE_AUTO = 0;
+/** @var int */
+const XSL_CLONE_NEVER = -1;
+/** @var int */
+const XSL_CLONE_ALWAYS = 1;
+
+/**
+ * @var int
+ * @cvalue XSL_SECPREF_NONE
+ */
+const XSL_SECPREF_NONE = UNKNOWN;
+/**
+ * @var int
+ * @cvalue XSL_SECPREF_READ_FILE
+ */
+const XSL_SECPREF_READ_FILE = UNKNOWN;
+/**
+ * @var int
+ * @cvalue XSL_SECPREF_WRITE_FILE
+ */
+const XSL_SECPREF_WRITE_FILE = UNKNOWN;
+/**
+ * @var int
+ * @cvalue XSL_SECPREF_CREATE_DIRECTORY
+ */
+const XSL_SECPREF_CREATE_DIRECTORY = UNKNOWN;
+/**
+ * @var int
+ * @cvalue XSL_SECPREF_READ_NETWORK
+ */
+const XSL_SECPREF_READ_NETWORK = UNKNOWN;
+/**
+ * @var int
+ * @cvalue XSL_SECPREF_WRITE_NETWORK
+ */
+const XSL_SECPREF_WRITE_NETWORK = UNKNOWN;
+/**
+ * @var int
+ * @cvalue XSL_SECPREF_DEFAULT
+ */
+const XSL_SECPREF_DEFAULT = UNKNOWN;
+
+/**
+ * @var int
+ * @cvalue LIBXSLT_VERSION
+ */
+const LIBXSLT_VERSION = UNKNOWN;
+/**
+ * @var string
+ * @cvalue LIBXSLT_DOTTED_VERSION
+ */
+const LIBXSLT_DOTTED_VERSION = UNKNOWN;
+
+#ifdef HAVE_XSL_EXSLT
+/**
+ * @var int
+ * @cvalue LIBEXSLT_VERSION
+ */
+const LIBEXSLT_VERSION = UNKNOWN;
+/**
+ * @var string
+ * @cvalue LIBEXSLT_DOTTED_VERSION
+ */
+const LIBEXSLT_DOTTED_VERSION = UNKNOWN;
+#endif
+
+class XSLTProcessor
+{
+    public bool $doXInclude = false;
+
+    public bool $cloneDocument = false;
+
+    public int $maxTemplateDepth;
+
+    public int $maxTemplateVars;
+
+    /**
+     * @param DOMDocument|DOM\Document|SimpleXMLElement $stylesheet
+     * @tentative-return-type
+     */
+    public function importStylesheet(object $stylesheet): bool {}
+
+    /**
+     * @param DOMDocument|DOM\Document|SimpleXMLElement $document
+     * @tentative-return-type
+     */
+    public function transformToDoc(object $document, ?string $returnClass = null): object|false {}
+
+    /**
+     * @param DOMDocument|DOM\Document|SimpleXMLElement $document
+     * @tentative-return-type
+     */
+    public function transformToUri(object $document, string $uri): int {}
+
+    /**
+     * @param DOMDocument|DOM\Document|SimpleXMLElement $document
+     * @tentative-return-type
+     */
+    public function transformToXml(object $document): string|null|false {}
+
+    /** @tentative-return-type */
+    public function setParameter(string $namespace, array|string $name, ?string $value = null): bool {}
+
+    /** @tentative-return-type */
+    public function getParameter(string $namespace, string $name): string|false {}
+
+    /** @tentative-return-type */
+    public function removeParameter(string $namespace, string $name): bool {}
+
+    /** @tentative-return-type */
+    public function hasExsltSupport(): bool {}
+
+    /** @tentative-return-type */
+    public function registerPHPFunctions(array|string|null $functions = null): void {}
+
+    public function registerPHPFunctionNS(string $namespaceURI, string $name, callable $callable): void {}
+
+    /** @tentative-return-type */
+    public function setProfiling(?string $filename): true {}
+
+    /** @tentative-return-type */
+    public function setSecurityPrefs(int $preferences): int {}
+
+    /** @tentative-return-type */
+    public function getSecurityPrefs(): int {}
+}
diff --git a/tests/Xml/Dom/Manipulator/Document/OptimizeNamespacesTest.php b/tests/Xml/Dom/Manipulator/Document/OptimizeNamespacesTest.php
index a775cb70..f9d2dc67 100644
--- a/tests/Xml/Dom/Manipulator/Document/OptimizeNamespacesTest.php
+++ b/tests/Xml/Dom/Manipulator/Document/OptimizeNamespacesTest.php
@@ -129,5 +129,29 @@ public function provideXmls()
             </ns1:foo>
             EOXML,
         ];
+        yield 'only-inline-namespace' => [
+            <<<EOXML
+            <foo xmlns="http://whatever">
+                <bar />
+            </foo>
+            EOXML,
+            <<<EOXML
+            <ns1:foo xmlns:ns1="http://whatever">
+                <ns1:bar/>
+            </ns1:foo>
+            EOXML,
+        ];
+        yield 'empty-namespace' => [
+            <<<EOXML
+            <foo xmlns="">
+                <bar />
+            </foo>
+            EOXML,
+            <<<EOXML
+            <foo xmlns="">
+                <bar/>
+            </foo>
+            EOXML,
+        ];
     }
 }