Use of BeforeParserrenderImageGallery hook... was deprecated in MediaWiki 1.35.

[The-Voidwalker]

The release notes indicate there is no replacement, so I'm not certain what needs to be do fix. Though, a vague recommendation is made that "MediaHandler provides for customizable media rendering", which may or may not prove useful here.

[lkucharczyk]

I would need another way to grab image data from gallery strip markers then.

mediawiki-PortableInfobox/includes/services/Parser/Nodes/NodeMedia.php

Lines 32 to 40 in eb05dd2

	public static function getGalleryData( $marker ) {
	$gallery = PortableInfoboxDataBag::getInstance()->getGallery( $marker );
	return isset( $gallery ) ? array_map( function ( $image ) {
	return [
	'label' => $image[1],
	'title' => $image[0]
	];
	}, $gallery->getimages() ) : [];
	}

I guess I could scrape parsed HTML, just like in tabber (same file; method below), but I would prefer a more elegant approach, so I leave that as a last resort.