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

See forge#70867

Description 

TYPO3's XLIFF parser now properly 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 are 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>
Copied!

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>
Copied!

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) will now display correctly without extra spaces or line breaks.

If you intentionally 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.