Feature: #97254 - Add Luxembourgish as supported language

See forge#97254

Description

TYPO3 now supports Luxembourgish out of the box.

Luxembourgish is one of the three administrative languages of Luxembourg (https://en.wikipedia.org/wiki/Luxembourgish).

The ISO 639-1 code for Luxembourgish is "lb", which is how TYPO3 is accessing the language internally.

Impact

It is now possible to

  • Fetch translated labels from translations.typo3.org / Crowdin automatically within the TYPO3 Backend
  • Switch the Backend Interface to Luxembourgish language
  • Create a new language in a site configuration using Luxembourgish
  • Create translation files with the "lb" prefix (such as lb.locallang.xlf) to create your own labels

and TYPO3 picks Luxembourgish as a language just like any other supported language.