Heroku (subsidiary of Salesforce) is a PaaS vendor. Some developers think they can setup MediaWiki easily and quickly there. There are recipes like https://gist.github.com/caseywatts/d04bda6626ef2c6c8f97 and https://firstname.lastname@example.org/host-mediawiki-on-heroku-2ed901c25b6c
The official "Buildpack" https://elements.heroku.com/buildpacks/youserve/heroku-mediawiki-buildpack is underwhelming with no documentation, and only 3 recent deploys at the time of writing freephile (talk) 14:23, 15 May 2023 (EDT)
However, these solutions don't even come close to simply downloading the MediaWiki tarball. Downloading the tarball isn't recommended if you want an Enterprise-grade MediaWiki.
Of course, the difference is that Heroku is a cloud-based containerized twelve-factor app "Platform as a Service" approach. So, to get all the benefits of twelve-factor, plus the carefully curated extensions and skins, just use Canasta. You can't deploy Canasta in your Heroku account, but you can deploy it to AWS plus your local laptop and any other host.