TYPO3 Core

the indexer configuration is the extension settings you can find in the settings.php

'indexed_search' => [
            'catdoc' => '/usr/bin/',
            'debugMode' => '0',
            'deleteFromIndexAfterEditing' => '1',
            'disableFrontendIndexing' => '0',
            'enableMetaphoneSearch' => '1',
            'flagBitMask' => '192',
            'fullTextDataLength' => '0',
            'ignoreExtensions' => '',
            'indexExternalURLs' => '0',
            'maxAge' => '0',
            'maxExternalFiles' => '5',
            'minAge' => '24',
            'pdf_mode' => '20',
            'pdftools' => '/usr/bin/',
            'ppthtml' => '/usr/bin/',
            'unrtf' => '/usr/bin/',
            'unzip' => '/usr/bin/',
            'useMysqlFulltext' => '0',
            'xlhtml' => '/usr/bin/',
        ],

this is written when installed, so the debugMode should be part of that. maybe you write this config on your own somewhere?

Patch set 1 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/82258

Applied in changeset 40217e05ba8b830f539b5dbceea590e084f6eae8.