Index: Source/web/typo3/sysext/extbase/Classes/Utility/LocalizationUtility.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/Source/web/typo3/sysext/extbase/Classes/Utility/LocalizationUtility.php b/Source/web/typo3/sysext/extbase/Classes/Utility/LocalizationUtility.php
--- a/Source/web/typo3/sysext/extbase/Classes/Utility/LocalizationUtility.php	(date 1611313296931)
+++ b/Source/web/typo3/sysext/extbase/Classes/Utility/LocalizationUtility.php	(date 1611313296931)
@@ -125,7 +125,16 @@
             // This unrolls arguments from $arguments - instead of calling vsprintf which receives arguments as an array.
             // The reason is that only sprintf() will return an error message if the number of arguments does not match
             // the number of placeholders in the format string. Whereas, vsprintf would silently return nothing.
-            return sprintf($value, ...array_values($arguments)) ?: sprintf('Error: could not translate key "%s" with value "%s" and %d argument(s)!', $key, $value, count($arguments));
+            try {
+                // PHP 8.0.0  sprintf no longer returns false on failure. 
+                return sprintf($value, ...array_values($arguments))?:sprintf('Error: could not translate key "%s" with value "%s" and %d argument(s)!', $key, $value, count($arguments));
+            }  catch ( \Exception $e ) {
+                throw new \InvalidArgumentException(
+                    sprintf('Error: could not translate key "%s" with value "%s" and %d argument(s)!', $key, $value, count($arguments)).
+                    "\nmessage: ".$e->getMessage(),
+                    1611312869
+                );
+            }
         }
         return $value;
     }