diff --git a/core/modules/update/src/ModuleVersion.php b/core/modules/update/src/ModuleVersion.php
index cec4abc95f..b25334b9f0 100644
--- a/core/modules/update/src/ModuleVersion.php
+++ b/core/modules/update/src/ModuleVersion.php
@@ -6,6 +6,8 @@
  * Provides a module version value object.
  *
  * @internal
+ *
+ * @see https://www.drupal.org/drupalorg/docs/apis/update-status-xml.
  */
 final class ModuleVersion {
 
@@ -50,7 +52,7 @@ public static function createFromVersionString($version_string) {
       if ($dot_x_position === 1 || $dot_x_position === 2) {
         $after_core_prefix = explode('.x-', $version_string)[1];
         if ($after_core_prefix !== 'dev') {
-          throw new \UnexpectedValueException("Unexpected version core prefix in $version_string. The only core prefix expected in \Drupal\update\ModuleVersion is '8.x-.");
+          throw new \UnexpectedValueException("Unexpected version core prefix in $version_string. The only core prefix expected in \Drupal\update\ModuleVersion is: 8.x-");
         }
       }
     }
@@ -66,7 +68,7 @@ public static function createFromVersionString($version_string) {
       // allowed is in development versions like 8.x-1.x-dev, 1.2.x-dev or
       // 1.x-dev.
        || (!is_numeric($last_part_split[0]) && $last_part_split !== 'x' && $version_extra !== 'dev')) {
-      throw new \UnexpectedValueException("Unexpected version number in $original_version.");
+      throw new \UnexpectedValueException("Unexpected version number in: $original_version");
     }
     return new static($major_version, $version_extra);
   }
diff --git a/core/modules/update/tests/src/Unit/ModuleVersionTest.php b/core/modules/update/tests/src/Unit/ModuleVersionTest.php
index 64465d2c00..ef3102d0ba 100644
--- a/core/modules/update/tests/src/Unit/ModuleVersionTest.php
+++ b/core/modules/update/tests/src/Unit/ModuleVersionTest.php
@@ -197,7 +197,7 @@ public function providerVersionInfos() {
    */
   public function testInvalidVersionNumber($version_string) {
     $this->expectException(\UnexpectedValueException::class);
-    $this->expectExceptionMessage("Unexpected version number in $version_string.");
+    $this->expectExceptionMessage("Unexpected version number in: $version_string");
     ModuleVersion::createFromVersionString($version_string);
   }
 
@@ -234,7 +234,7 @@ public function providerInvalidVersionNumber() {
    */
   public function testInvalidVersionCorePrefix($version_string) {
     $this->expectException(\UnexpectedValueException::class);
-    $this->expectExceptionMessage("Unexpected version core prefix in $version_string. The only core prefix expected in \Drupal\update\ModuleVersion is '8.x-.");
+    $this->expectExceptionMessage("Unexpected version core prefix in $version_string. The only core prefix expected in \Drupal\update\ModuleVersion is: 8.x-");
     ModuleVersion::createFromVersionString($version_string);
   }
 
@@ -254,10 +254,13 @@ public function providerInvalidVersionCorePrefix() {
    * @covers ::createFromSupportBranch
    *
    * @dataProvider providerInvalidBranchCorePrefix
+   *
+   * @param string $branch
+   *   The branch to test.
    */
   public function testInvalidBranchCorePrefix($branch) {
     $this->expectException(\UnexpectedValueException::class);
-    $this->expectExceptionMessage("Unexpected version core prefix in {$branch}0. The only core prefix expected in \Drupal\update\ModuleVersion is '8.x-.");
+    $this->expectExceptionMessage("Unexpected version core prefix in {$branch}0. The only core prefix expected in \Drupal\update\ModuleVersion is: 8.x-");
     ModuleVersion::createFromSupportBranch($branch);
   }
 
@@ -277,6 +280,12 @@ public function providerInvalidBranchCorePrefix() {
    * @covers ::createFromSupportBranch
    *
    * @dataProvider providerCreateFromSupportBranch
+   *
+   * @param string $branch
+   *   The branch to test.
+   *
+   * @param string $expected_major
+   *   The expected major version.
    */
   public function testCreateFromSupportBranch($branch, $expected_major) {
     $version = ModuleVersion::createFromSupportBranch($branch);
@@ -318,6 +327,9 @@ public function providerCreateFromSupportBranch() {
    * @covers ::createFromSupportBranch
    *
    * @dataProvider provideInvalidBranch
+   *
+   * @param string $branch
+   *   The branch to test.
    */
   public function testInvalidBranch($branch) {
     $this->expectException(\UnexpectedValueException::class);