Prior to SOLR-6058 the /solr/tutorial.html link on the website contained only a simple landing page that then linked people to the "versioned" tutorial for the most recent release – or more specificly: the most recent release*s* (plural) when we were releasing off of multiple branches (ie: links to both the 4.0.0 tutorial, as well as the 3.6.3 tutorial when 4.0 came out)
The old tutorial content lived along side the solr code, and was automatically branched, tagged & released along with Solr. When committing any changes to Solr code (or post.jar code, or the sample data, or the sample configs, etc..) you could also commit changes to the tutorial at th same time and be confident that it was clear what version of solr that tutorial went along with.
As part of SOLR-6058, it seems that there was a concensus to move to a keeping "tutorial" content on the website, where it can be integrated directly in with other site content/navigation, and use the same look and feel.
I have no objection to this in principle – but as a result of this choice, there are outstanding issues regarding how devs should go about maintaining this doc as changes are made to solr & the solr examples used in the tutorial.
We need a clear process for where/how to edit the tutorial(s) as new versions of solr come out and cahnges are made that mandate corisponding hanges to the tutorial. this process should also account for things like having multiple versions of the tutorial live at one time (ie: at some point in the future, we'll certainly need to host the "5.13" tutorial if that's the current "stable" release, but we'll also want to host the tutorial for "6.0-BETA" so that people can try it out)