ext_localconf.php

<?php
defined('TYPO3_MODE') || die();

$textFileExtensions = explode(',', $GLOBALS['TYPO3_CONF_VARS']['SYS']['textfile_ext']);
$textFileExtensions = array_merge($textFileExtensions, array('json', 'py', 'rst', 'yml'));
$GLOBALS['TYPO3_CONF_VARS']['SYS']['textfile_ext'] = implode(',', array_unique($textFileExtensions));

/** @var \TYPO3\CMS\Extbase\SignalSlot\Dispatcher $signalSlotDispatcher */
$signalSlotDispatcher = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance('TYPO3\\CMS\\Extbase\\SignalSlot\\Dispatcher');

// Hook into EXT:documentation
$signalSlotDispatcher->connect(
    'TYPO3\\CMS\\Documentation\\Controller\\DocumentController',
    'afterInitializeDocuments',
    'Causal\\Sphinx\\Slots\\SphinxDocumentation',
    'postProcessDocuments'
);

// Hook into ourselves to post-process LaTeX generated files
$signalSlotDispatcher->connect(
    'Causal\\Sphinx\\Utility\\SphinxBuilder',
    'afterBuildLatex',
    'Causal\\Sphinx\\Slots\\LatexPostProcessor',
    'postprocess'
);

// Hook into ourselves to handle custom projects
$signalSlotDispatcher->connect(
    'Causal\\Sphinx\\Controller\\DocumentationController',
    'afterInitializeReferences',
    'Causal\\Sphinx\\Slots\\CustomProject',
    'postprocessReferences'
);

$signalSlotDispatcher->connect(
    'Causal\\Sphinx\\Controller\\DocumentationController',
    'renderUserDocumentation',
    'Causal\\Sphinx\\Slots\\CustomProject',
    'render'
);

$signalSlotDispatcher->connect(
    'Causal\\Sphinx\\Controller\\InteractiveViewerController',
    'retrieveBasePath',
    'Causal\\Sphinx\\Slots\\CustomProject',
    'retrieveBasePath'
);

$signalSlotDispatcher->connect(
    'Causal\\Sphinx\\Controller\\RestEditorController',
    'retrieveRestFilename',
    'Causal\\Sphinx\\Slots\\CustomProject',
    'retrieveRestFilename'
);