7 uses of UNICODE_MULTIBYTE

drupal_strlen in drupal/core/includes/unicode.inc
Count the amount of characters in a UTF-8 string. This is less than or equal to the byte count.
drupal_strtolower in drupal/core/includes/unicode.inc
Lowercase a UTF-8 string.
drupal_strtoupper in drupal/core/includes/unicode.inc
Uppercase a UTF-8 string.
drupal_substr in drupal/core/includes/unicode.inc
Cut off a piece of a string based on character indices and counts. Follows the same behavior as PHP's own substr() function.
HandlerBase::caseTransform in drupal/core/modules/views/lib/Drupal/views/Plugin/views/HandlerBase.php
Transform a string by a certain method.
UnicodeUnitTest::testMbStringUnicode in drupal/core/modules/system/lib/Drupal/system/Tests/System/UnicodeUnitTest.php
Test full unicode features implemented using the mbstring extension.
unicode_check in drupal/core/includes/bootstrap.inc
Checks for Unicode support in PHP and sets the proper settings if possible.