TYPO3 Core

The following labels referenced in typo3/sysext/core/Configuration/TCA/pages.php

        'shortcut' => [
            'label' => 'LLL:EXT:frontend/Resources/Private/Language/locallang_tca.xlf:pages.palettes.shortcut',
            'showitem' => 'shortcut_mode;LLL:EXT:frontend/Resources/Private/Language/locallang_tca.xlf:pages.shortcut_mode_formlabel',
        ],
        'shortcutpage' => [
            'label' => 'LLL:EXT:frontend/Resources/Private/Language/locallang_tca.xlf:pages.palettes.shortcutpage',
            'showitem' => 'shortcut;LLL:EXT:frontend/Resources/Private/Language/locallang_tca.xlf:pages.shortcut_formlabel',
        ],
        'mountpoint' => [
            'label' => 'LLL:EXT:frontend/Resources/Private/Language/locallang_tca.xlf:pages.palettes.mountpoint',
            'showitem' => 'mount_pid_ol;LLL:EXT:frontend/Resources/Private/Language/locallang_tca.xlf:pages.mount_pid_ol_formlabel',
        ],
        'mountpage' => [
            'label' => 'LLL:EXT:frontend/Resources/Private/Language/locallang_tca.xlf:pages.palettes.mountpage',
            'showitem' => 'mount_pid;LLL:EXT:frontend/Resources/Private/Language/locallang_tca.xlf:pages.mount_pid_formlabel',
        ],
        'external' => [
            'label' => 'LLL:EXT:frontend/Resources/Private/Language/locallang_tca.xlf:pages.palettes.external',
            'showitem' => 'url;LLL:EXT:frontend/Resources/Private/Language/locallang_tca.xlf:pages.url_formlabel',
        ],

do not exist in EXT:frontend/Resources/Private/Language/locallang_tca.xlf - they either must be added there or removed from the TCA definition.