[TYPO3-core] RFC: #16136: Change behaviour of check for allowed file extensions -> make it possible to really restrict to certain file extensions for filemounts

[Andreas Kiessling]

Hi Steffen,

>
> Committed to trunk rev. 9288
> Docs have been added to Pending Documentation page.
>
> Thanks for your contribution, Andreas! Go on ;)

Thanks for reviewing and comitting.
What about the unit test?

Regards,
Andreas