I continue to test the latest Wikibase Release Pipeline.
It seems that setting MW_SITE_NAME env-variable doesn't change 'wikibase-docker' title in Wikibase frontend. So with Timeless-skin in search box it's written "Search in wikibase-docker", but it should be "Search in MW_SITE_NAME".
In previous Docker releases setting MW_SITE_NAME env-variable changed that title...