Description:
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Pathinfo will strip umlauts from the filename beginning if locale is not correct set.

The strange thing is that it will not strip other umlauts for example if they are in the middle of the string.

I would expect that it strips all umlauts or none but not that it will strip them from the beginning but not in the string.

Test script:
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<?php

setlocale(LC_ALL, 'C');

echo pathinfo('änderungs', PATHINFO_FILENAME) . PHP_EOL;

echo pathinfo('bestandübertragung', PATHINFO_FILENAME) . PHP_EOL;

Expected result:
----------------
änderungs
bestandübertragung


Actual result:
--------------
nderungs
bestandübertragung