Important: #70867 - XLIFF whitespace handling now respects xml:space 

Description 

TYPO3's XLIFF parser now respects the xml:space attribute according to the XML specification (https://www.w3.org/TR/xml/#sec-white-space).

This affects how whitespace (spaces, tabs, newlines) in translation strings is handled.

Without xml:space="preserve" (default behavior):

Multiple consecutive whitespace characters (spaces, tabs, newlines) are collapsed into a single space, and leading/trailing whitespace is trimmed.

Example XLIFF source:

<trans-unit id="my.label">
  <source>This is a
    multi-line
    string.</source>
</trans-unit>

Before: The string contained literal newlines and indentation. After: The string becomes "This is a multi-line string."

With xml:space="preserve":

Whitespace is kept exactly as written in the XLIFF file.

<trans-unit id="my.label" xml:space="preserve">
  <source>This is a
    multi-line
    string.</source>
</trans-unit>

The string remains "This is a\n multi-line\n string."

Impact 

Translation strings that previously contained unintended whitespace (from formatting in the XLIFF file) are now correctly displayed without extra spaces or line breaks.

If you need preserved whitespace in a translation string, add the xml:space="preserve" attribute to the <trans-unit> element (XLIFF 1.2) or <segment> element (XLIFF 2.0).

This change affects both XLIFF 1.2 and XLIFF 2.0/2.1 formats.