TYPO3 Core

These for example are some of the files, and here they are in Pootle

As far as I know, currently no xlf files get excluded anywhere and I would not like to add some magic here.

I propose to add a developer note, e.g. like so:

<trans-unit id="label1">
    <source>This is my 1st label</source>
    <note from="developer">This label is part of a test suite; it is not actually used in the interface of TYPO3 CMS.</note>
</trans-unit>

This note will then be shown in the Pootle interface just like our "deprecation" and "do not translate" notes as well.

with upcoming solution using Crowdin those files won't be provided to translators anymore.