TYPO3 8 LTS doesn't find the ext:lang translations when using .xml, this is because the xlf files where moved to a subfolder and the core only remaps xlf.
LLL:EXT:lang/locallang_general.xml would be LLL:EXT:lang/Resources/Private/Language/locallang_general.xlf, but this doesn't work in 7LTS. LLL:EXT:lang/locallang_general.xlf works in both but is deprecated now.
this is only tested in TYPO3 7 and 8 LTS not in 6LTS
TYPO3 8 LTS doesn't find the ext:lang translations when using .xml, this is because the xlf files where moved to a subfolder and the core only remaps xlf.
see: https://docs.typo3.org/typo3cms/extensions/core/Changelog/8.5/Deprecation-78647-MoveLanguageFilesFromEXTlanglocallang_ToResourcesPrivateLanguage.html
LLL:EXT:lang/locallang_general.xml would be LLL:EXT:lang/Resources/Private/Language/locallang_general.xlf, but this doesn't work in 7LTS. LLL:EXT:lang/locallang_general.xlf works in both but is deprecated now.
this is only tested in TYPO3 7 and 8 LTS not in 6LTS