diff --git a/public/lib/psr/cache/CHANGELOG.md b/public/lib/psr/cache/CHANGELOG.md
new file mode 100644
index 00000000000..58ddab05aa1
--- /dev/null
+++ b/public/lib/psr/cache/CHANGELOG.md
@@ -0,0 +1,16 @@
+# Changelog
+
+All notable changes to this project will be documented in this file, in reverse chronological order by release.
+
+## 1.0.1 - 2016-08-06
+
+### Fixed
+
+- Make spacing consistent in phpdoc annotations php-fig/cache#9 - chalasr
+- Fix grammar in phpdoc annotations php-fig/cache#10 - chalasr
+- Be more specific in docblocks that `getItems()` and `deleteItems()` take an array of strings (`string[]`) compared to just `array` php-fig/cache#8 - GrahamCampbell
+- For `expiresAt()` and `expiresAfter()` in CacheItemInterface fix docblock to specify null as a valid parameters as well as an implementation of DateTimeInterface php-fig/cache#7 - GrahamCampbell
+
+## 1.0.0 - 2015-12-11
+
+Initial stable release; reflects accepted PSR-6 specification
diff --git a/public/lib/psr/cache/LICENSE.txt b/public/lib/psr/cache/LICENSE.txt
new file mode 100644
index 00000000000..b1c2c97b9d4
--- /dev/null
+++ b/public/lib/psr/cache/LICENSE.txt
@@ -0,0 +1,19 @@
+Copyright (c) 2015 PHP Framework Interoperability Group
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/public/lib/psr/cache/README.md b/public/lib/psr/cache/README.md
new file mode 100644
index 00000000000..9855a318bd4
--- /dev/null
+++ b/public/lib/psr/cache/README.md
@@ -0,0 +1,12 @@
+Caching Interface
+==============
+
+This repository holds all interfaces related to [PSR-6 (Caching Interface)][psr-url].
+
+Note that this is not a Caching implementation of its own. It is merely interfaces that describe the components of a Caching mechanism.
+
+The installable [package][package-url] and [implementations][implementation-url] are listed on Packagist.
+
+[psr-url]: https://www.php-fig.org/psr/psr-6/
+[package-url]: https://packagist.org/packages/psr/cache
+[implementation-url]: https://packagist.org/providers/psr/cache-implementation
diff --git a/public/lib/psr/cache/composer.json b/public/lib/psr/cache/composer.json
new file mode 100644
index 00000000000..4b687971e4c
--- /dev/null
+++ b/public/lib/psr/cache/composer.json
@@ -0,0 +1,25 @@
+{
+    "name": "psr/cache",
+    "description": "Common interface for caching libraries",
+    "keywords": ["psr", "psr-6", "cache"],
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "PHP-FIG",
+            "homepage": "https://www.php-fig.org/"
+        }
+    ],
+    "require": {
+        "php": ">=8.0.0"
+    },
+    "autoload": {
+        "psr-4": {
+            "Psr\\Cache\\": "src/"
+        }
+    },
+    "extra": {
+        "branch-alias": {
+            "dev-master": "1.0.x-dev"
+        }
+    }
+}
diff --git a/public/lib/psr/cache/readme_moodle.txt b/public/lib/psr/cache/readme_moodle.txt
new file mode 100644
index 00000000000..e741f3e425a
--- /dev/null
+++ b/public/lib/psr/cache/readme_moodle.txt
@@ -0,0 +1,10 @@
+# Caching Interface (PSR-6)
+
+This is a description for including the Caching Interface (PSR-6) in Moodle
+
+## Installation
+
+1. Visit https://github.com/php-fig/cache
+2. Download the latest release
+3. Unzip in this folder
+4. Update `thirdpartylibs.xml`
diff --git a/public/lib/psr/cache/src/CacheException.php b/public/lib/psr/cache/src/CacheException.php
new file mode 100644
index 00000000000..bb785f46ceb
--- /dev/null
+++ b/public/lib/psr/cache/src/CacheException.php
@@ -0,0 +1,10 @@
+<?php
+
+namespace Psr\Cache;
+
+/**
+ * Exception interface for all exceptions thrown by an Implementing Library.
+ */
+interface CacheException extends \Throwable
+{
+}
diff --git a/public/lib/psr/cache/src/CacheItemInterface.php b/public/lib/psr/cache/src/CacheItemInterface.php
new file mode 100644
index 00000000000..2b2e4bb88f6
--- /dev/null
+++ b/public/lib/psr/cache/src/CacheItemInterface.php
@@ -0,0 +1,105 @@
+<?php
+
+namespace Psr\Cache;
+
+/**
+ * CacheItemInterface defines an interface for interacting with objects inside a cache.
+ *
+ * Each Item object MUST be associated with a specific key, which can be set
+ * according to the implementing system and is typically passed by the
+ * Cache\CacheItemPoolInterface object.
+ *
+ * The Cache\CacheItemInterface object encapsulates the storage and retrieval of
+ * cache items. Each Cache\CacheItemInterface is generated by a
+ * Cache\CacheItemPoolInterface object, which is responsible for any required
+ * setup as well as associating the object with a unique Key.
+ * Cache\CacheItemInterface objects MUST be able to store and retrieve any type
+ * of PHP value defined in the Data section of the specification.
+ *
+ * Calling Libraries MUST NOT instantiate Item objects themselves. They may only
+ * be requested from a Pool object via the getItem() method.  Calling Libraries
+ * SHOULD NOT assume that an Item created by one Implementing Library is
+ * compatible with a Pool from another Implementing Library.
+ */
+interface CacheItemInterface
+{
+    /**
+     * Returns the key for the current cache item.
+     *
+     * The key is loaded by the Implementing Library, but should be available to
+     * the higher level callers when needed.
+     *
+     * @return string
+     *   The key string for this cache item.
+     */
+    public function getKey(): string;
+
+    /**
+     * Retrieves the value of the item from the cache associated with this object's key.
+     *
+     * The value returned must be identical to the value originally stored by set().
+     *
+     * If isHit() returns false, this method MUST return null. Note that null
+     * is a legitimate cached value, so the isHit() method SHOULD be used to
+     * differentiate between "null value was found" and "no value was found."
+     *
+     * @return mixed
+     *   The value corresponding to this cache item's key, or null if not found.
+     */
+    public function get(): mixed;
+
+    /**
+     * Confirms if the cache item lookup resulted in a cache hit.
+     *
+     * Note: This method MUST NOT have a race condition between calling isHit()
+     * and calling get().
+     *
+     * @return bool
+     *   True if the request resulted in a cache hit. False otherwise.
+     */
+    public function isHit(): bool;
+
+    /**
+     * Sets the value represented by this cache item.
+     *
+     * The $value argument may be any item that can be serialized by PHP,
+     * although the method of serialization is left up to the Implementing
+     * Library.
+     *
+     * @param mixed $value
+     *   The serializable value to be stored.
+     *
+     * @return static
+     *   The invoked object.
+     */
+    public function set(mixed $value): static;
+
+    /**
+     * Sets the expiration time for this cache item.
+     *
+     * @param ?\DateTimeInterface $expiration
+     *   The point in time after which the item MUST be considered expired.
+     *   If null is passed explicitly, a default value MAY be used. If none is set,
+     *   the value should be stored permanently or for as long as the
+     *   implementation allows.
+     *
+     * @return static
+     *   The called object.
+     */
+    public function expiresAt(?\DateTimeInterface $expiration): static;
+
+    /**
+     * Sets the expiration time for this cache item.
+     *
+     * @param int|\DateInterval|null $time
+     *   The period of time from the present after which the item MUST be considered
+     *   expired. An integer parameter is understood to be the time in seconds until
+     *   expiration. If null is passed explicitly, a default value MAY be used.
+     *   If none is set, the value should be stored permanently or for as long as the
+     *   implementation allows.
+     *
+     * @return static
+     *   The called object.
+     */
+    public function expiresAfter(int|\DateInterval|null $time): static;
+}
diff --git a/public/lib/psr/cache/src/CacheItemPoolInterface.php b/public/lib/psr/cache/src/CacheItemPoolInterface.php
new file mode 100644
index 00000000000..4b3017c75e9
--- /dev/null
+++ b/public/lib/psr/cache/src/CacheItemPoolInterface.php
@@ -0,0 +1,138 @@
+<?php
+
+namespace Psr\Cache;
+
+/**
+ * CacheItemPoolInterface generates CacheItemInterface objects.
+ *
+ * The primary purpose of Cache\CacheItemPoolInterface is to accept a key from
+ * the Calling Library and return the associated Cache\CacheItemInterface object.
+ * It is also the primary point of interaction with the entire cache collection.
+ * All configuration and initialization of the Pool is left up to an
+ * Implementing Library.
+ */
+interface CacheItemPoolInterface
+{
+    /**
+     * Returns a Cache Item representing the specified key.
+     *
+     * This method must always return a CacheItemInterface object, even in case of
+     * a cache miss. It MUST NOT return null.
+     *
+     * @param string $key
+     *   The key for which to return the corresponding Cache Item.
+     *
+     * @throws InvalidArgumentException
+     *   If the $key string is not a legal value a \Psr\Cache\InvalidArgumentException
+     *   MUST be thrown.
+     *
+     * @return CacheItemInterface
+     *   The corresponding Cache Item.
+     */
+    public function getItem(string $key): CacheItemInterface;
+
+    /**
+     * Returns a traversable set of cache items.
+     *
+     * @param string[] $keys
+     *   An indexed array of keys of items to retrieve.
+     *
+     * @throws InvalidArgumentException
+     *   If any of the keys in $keys are not a legal value a \Psr\Cache\InvalidArgumentException
+     *   MUST be thrown.
+     *
+     * @return iterable
+     *   An iterable collection of Cache Items keyed by the cache keys of
+     *   each item. A Cache item will be returned for each key, even if that
+     *   key is not found. However, if no keys are specified then an empty
+     *   traversable MUST be returned instead.
+     */
+    public function getItems(array $keys = []): iterable;
+
+    /**
+     * Confirms if the cache contains specified cache item.
+     *
+     * Note: This method MAY avoid retrieving the cached value for performance reasons.
+     * This could result in a race condition with CacheItemInterface::get(). To avoid
+     * such situation use CacheItemInterface::isHit() instead.
+     *
+     * @param string $key
+     *   The key for which to check existence.
+     *
+     * @throws InvalidArgumentException
+     *   If the $key string is not a legal value a \Psr\Cache\InvalidArgumentException
+     *   MUST be thrown.
+     *
+     * @return bool
+     *   True if item exists in the cache, false otherwise.
+     */
+    public function hasItem(string $key): bool;
+
+    /**
+     * Deletes all items in the pool.
+     *
+     * @return bool
+     *   True if the pool was successfully cleared. False if there was an error.
+     */
+    public function clear(): bool;
+
+    /**
+     * Removes the item from the pool.
+     *
+     * @param string $key
+     *   The key to delete.
+     *
+     * @throws InvalidArgumentException
+     *   If the $key string is not a legal value a \Psr\Cache\InvalidArgumentException
+     *   MUST be thrown.
+     *
+     * @return bool
+     *   True if the item was successfully removed. False if there was an error.
+     */
+    public function deleteItem(string $key): bool;
+
+    /**
+     * Removes multiple items from the pool.
+     *
+     * @param string[] $keys
+     *   An array of keys that should be removed from the pool.
+     *
+     * @throws InvalidArgumentException
+     *   If any of the keys in $keys are not a legal value a \Psr\Cache\InvalidArgumentException
+     *   MUST be thrown.
+     *
+     * @return bool
+     *   True if the items were successfully removed. False if there was an error.
+     */
+    public function deleteItems(array $keys): bool;
+
+    /**
+     * Persists a cache item immediately.
+     *
+     * @param CacheItemInterface $item
+     *   The cache item to save.
+     *
+     * @return bool
+     *   True if the item was successfully persisted. False if there was an error.
+     */
+    public function save(CacheItemInterface $item): bool;
+
+    /**
+     * Sets a cache item to be persisted later.
+     *
+     * @param CacheItemInterface $item
+     *   The cache item to save.
+     *
+     * @return bool
+     *   False if the item could not be queued or if a commit was attempted and failed. True otherwise.
+     */
+    public function saveDeferred(CacheItemInterface $item): bool;
+
+    /**
+     * Persists any deferred cache items.
+     *
+     * @return bool
+     *   True if all not-yet-saved items were successfully saved or there were none. False otherwise.
+     */
+    public function commit(): bool;
+}
diff --git a/public/lib/psr/cache/src/InvalidArgumentException.php b/public/lib/psr/cache/src/InvalidArgumentException.php
new file mode 100644
index 00000000000..be7c6fa0ef1
--- /dev/null
+++ b/public/lib/psr/cache/src/InvalidArgumentException.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Psr\Cache;
+
+/**
+ * Exception interface for invalid cache arguments.
+ *
+ * Any time an invalid argument is passed into a method it must throw an
+ * exception class which implements Psr\Cache\InvalidArgumentException.
+ */
+interface InvalidArgumentException extends CacheException
+{
+}
diff --git a/public/lib/thirdpartylibs.xml b/public/lib/thirdpartylibs.xml
index a6d65ff481d..9eac8da5e26 100644
--- a/public/lib/thirdpartylibs.xml
+++ b/public/lib/thirdpartylibs.xml
@@ -847,4 +847,12 @@ All rights reserved.</copyright>
       <license>MIT</license>
       <repository>https://github.com/Seldaek/monolog</repository>
   </library>
+  <library>
+      <location>psr/cache</location>
+      <name>cache</name>
+      <description>Caching Interface (PHP FIG PSR-6).</description>
+      <version>3.0.0</version>
+      <license>MIT</license>
+      <repository>https://github.com/php-fig/cache</repository>
+  </library>
 </libraries>