@Mainframe98 I guess that I have to move:

function onBeforePageDisplay(&$out)
{
	$out->addModules('ext.biblioPlus.qtip.config');
	return true;
}

function biblioPlusSetup( Parser $parser ) {
	$biblio = new BiblioPlus;
	$parser -> setHook("cite", array($biblio,'biblioRenderCite'));
	$parser -> setHook("nocite", array($biblio, 'biblioRenderNocite'));
	$parser -> setHook("biblio", array($biblio, 'biblioRenderBiblio'));
	return true;
}

out of BiblioPlus.php. Not sure where though. One file, two?

It'd be best to create a separate Hooks class with those two functions in it. Something like BiblioPlus.hooks.php.

I'll try that. Thanks.

Change 405910 had a related patch set uploaded (by MarcoAurelio; owner: MarcoAurelio):
[mediawiki/extensions/BiblioPlus@master] Convert BiblioPlus to use extension registration

https://gerrit.wikimedia.org/r/405910

@Mainframe98 Done; however jenkins complains for some reason :)

Change 405910 merged by jenkins-bot:
[mediawiki/extensions/BiblioPlus@master] Convert BiblioPlus to use extension registration

https://gerrit.wikimedia.org/r/405910