diff --git a/composer/autoload.php b/composer/autoload.php
index 252d6688664..00a30bcd1ae 100644
--- a/composer/autoload.php
+++ b/composer/autoload.php
@@ -14,10 +14,7 @@
             echo $err;
         }
     }
-    trigger_error(
-        $err,
-        E_USER_ERROR
-    );
+    throw new RuntimeException($err);
 }
 
 require_once __DIR__ . '/composer/autoload_real.php';
diff --git a/composer/composer/InstalledVersions.php b/composer/composer/InstalledVersions.php
index 6d29bff66aa..2052022fd8e 100644
--- a/composer/composer/InstalledVersions.php
+++ b/composer/composer/InstalledVersions.php
@@ -26,6 +26,12 @@
  */
 class InstalledVersions
 {
+    /**
+     * @var string|null if set (by reflection by Composer), this should be set to the path where this class is being copied to
+     * @internal
+     */
+    private static $selfDir = null;
+
     /**
      * @var mixed[]|null
      * @psalm-var array{root: array{name: string, pretty_version: string, version: string, reference: string|null, type: string, install_path: string, aliases: string[], dev: bool}, versions: array<string, array{pretty_version?: string, version?: string, reference?: string|null, type?: string, install_path?: string, aliases?: string[], dev_requirement: bool, replaced?: string[], provided?: string[]}>}|array{}|null
@@ -322,6 +328,18 @@ public static function reload($data)
         self::$installedIsLocalDir = false;
     }
 
+    /**
+     * @return string
+     */
+    private static function getSelfDir()
+    {
+        if (self::$selfDir === null) {
+            self::$selfDir = strtr(__DIR__, '\\', '/');
+        }
+
+        return self::$selfDir;
+    }
+
     /**
      * @return array[]
      * @psalm-return list<array{root: array{name: string, pretty_version: string, version: string, reference: string|null, type: string, install_path: string, aliases: string[], dev: bool}, versions: array<string, array{pretty_version?: string, version?: string, reference?: string|null, type?: string, install_path?: string, aliases?: string[], dev_requirement: bool, replaced?: string[], provided?: string[]}>}>
@@ -336,7 +354,7 @@ private static function getInstalled()
         $copiedLocalDir = false;
 
         if (self::$canGetVendors) {
-            $selfDir = strtr(__DIR__, '\\', '/');
+            $selfDir = self::getSelfDir();
             foreach (ClassLoader::getRegisteredLoaders() as $vendorDir => $loader) {
                 $vendorDir = strtr($vendorDir, '\\', '/');
                 if (isset(self::$installedByVendor[$vendorDir])) {
diff --git a/lib/DirectEditing/TextDirectEditor.php b/lib/DirectEditing/TextDirectEditor.php
index 01276d14bec..ac1a7b9c578 100644
--- a/lib/DirectEditing/TextDirectEditor.php
+++ b/lib/DirectEditing/TextDirectEditor.php
@@ -17,6 +17,7 @@
 use OCP\Files\InvalidPathException;
 use OCP\Files\NotFoundException;
 use OCP\Files\NotPermittedException;
+use OCP\IAppConfig;
 use OCP\IL10N;
 use OCP\Util;
 
@@ -31,10 +32,16 @@ class TextDirectEditor implements IEditor {
 	/** @var ApiService */
 	private $apiService;
 
-	public function __construct(IL10N $l10n, InitialStateProvider $initialStateProvider, ApiService $apiService) {
+	/**
+	 * @var IAppConfig
+	 */
+	private $appConfig;
+
+	public function __construct(IL10N $l10n, InitialStateProvider $initialStateProvider, ApiService $apiService, IAppConfig $appConfig) {
 		$this->l10n = $l10n;
 		$this->initialStateProvider = $initialStateProvider;
 		$this->apiService = $apiService;
+		$this->appConfig = $appConfig;
 	}
 
 	/**
@@ -109,7 +116,7 @@ public function getMimetypesOptional(): array {
 	 */
 	public function getCreators(): array {
 		return [
-			new TextDocumentCreator($this->l10n),
+			new TextDocumentCreator($this->l10n, $this->appConfig),
 		];
 	}
 
diff --git a/lib/DirectEditing/TextDocumentCreator.php b/lib/DirectEditing/TextDocumentCreator.php
index 56cc5019d92..c35eb428a6a 100644
--- a/lib/DirectEditing/TextDocumentCreator.php
+++ b/lib/DirectEditing/TextDocumentCreator.php
@@ -7,6 +7,7 @@
 namespace OCA\Text\DirectEditing;
 
 use OCP\DirectEditing\ACreateEmpty;
+use OCP\IAppConfig;
 use OCP\IL10N;
 
 class TextDocumentCreator extends ACreateEmpty {
@@ -17,8 +18,14 @@ class TextDocumentCreator extends ACreateEmpty {
 	 */
 	private $l10n;
 
-	public function __construct(IL10N $l10n) {
+	/**
+	 * @var IAppConfig
+	 */
+	private $appConfig;
+
+	public function __construct(IL10N $l10n, IAppConfig $appConfig) {
 		$this->l10n = $l10n;
+		$this->appConfig = $appConfig;
 	}
 
 	public function getId(): string {
@@ -30,10 +37,16 @@ public function getName(): string {
 	}
 
 	public function getExtension(): string {
-		return 'md';
+		return $this->appConfig->getValueString('text', 'default_file_extension', 'md');
 	}
 
 	public function getMimetype(): string {
-		return 'text/markdown';
+		switch ($this->getExtension()) {
+			case 'txt':
+				return 'text/plain';
+			case 'md':
+			default:
+				return 'text/markdown';
+		}
 	}
 }
diff --git a/tests/unit/DirectEditing/TextDocumentCreatorTest.php b/tests/unit/DirectEditing/TextDocumentCreatorTest.php
new file mode 100644
index 00000000000..a19acf96aa5
--- /dev/null
+++ b/tests/unit/DirectEditing/TextDocumentCreatorTest.php
@@ -0,0 +1,68 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2019 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Text\Tests;
+
+use OCA\Text\DirectEditing\TextDocumentCreator;
+use OCP\IAppConfig;
+use OCP\IL10N;
+
+class TextDocumentCreatorTest extends \PHPUnit\Framework\TestCase {
+	private TextDocumentCreator $textDocumentCreator;
+
+	private IL10N $l10n;
+
+	private IAppConfig $appConfig;
+
+	protected function setUp(): void {
+		$this->l10n = $this->createMock(IL10N::class);
+		$this->appConfig = $this->createMock(IAppConfig::class);
+		$this->textDocumentCreator = new TextDocumentCreator($this->l10n, $this->appConfig);
+	}
+
+	public function testGetId(): void {
+		$this->assertEquals('textdocument', $this->textDocumentCreator->getId());
+	}
+
+	public function testGetName(): void {
+		$this->l10n->expects($this->once())
+			->method('t')
+			->with('text document')
+			->willReturn('text document');
+		$this->assertEquals('text document', $this->textDocumentCreator->getName());
+	}
+
+	public function testGetDefaultExtension(): void {
+		$this->appConfig->expects($this->once())
+			->method('getValueString')
+			->with('text', 'default_file_extension', 'md')
+			->willReturn('md');
+		$this->assertEquals('md', $this->textDocumentCreator->getExtension());
+	}
+
+	public function testGetExtensionFromConfig(): void {
+		$this->appConfig->expects($this->once())
+			->method('getValueString')
+			->with('text', 'default_file_extension', 'md')
+			->willReturn('txt');
+
+		$this->assertEquals('txt', $this->textDocumentCreator->getExtension());
+	}
+
+	public function testGetDefaultMimetype(): void {
+		$this->assertEquals('text/markdown', $this->textDocumentCreator->getMimetype());
+	}
+
+	public function testGetMimetypeFromConfig(): void {
+		$this->appConfig->expects($this->once())
+			->method('getValueString')
+			->with('text', 'default_file_extension', 'md')
+			->willReturn('txt');
+
+		$this->assertEquals('text/plain', $this->textDocumentCreator->getMimetype());
+	}
+}