Remove support for installing install profiles via the UI installer

I'm generally +1 for this, because I like anything that streamlines the installer and gets people up and running more quickly.

Re-titling, because pre-selected profiles (pre-filled settings.php, distributions), will still be supported. The only thing we'd be removing here is the form/step for install profile selection.

I think Drupal CMS 2.0 will change from the recipe picker to a site template picker with the built-in site templates as options. So I would not yet go towards what CMS 1.0 does :) In a way the site templates are more similar to the install profiles (in concept, not in technology!) than recipes were :) I don't think site templates will be install profiles at all though, so I think the install profile selector will not come back in CMS for sure.

I opened 📌 Deprecate and remove the Umami demonstration profile from core, make it a contributed site template Active to free Umami from core and revitalise it in contrib as a contrib site template showcase :)

I think as long a we have Umami in core only (and not in contrib), it would be sad if there would be no UI to select it.
After all we created Umami for those that do not necessarily work well with a CLI.

Isn't that already being fulfilled by Drupal CMS now though? Especially given it's the default download on https://new.drupal.org/download

If we're not going to convert Umami to a recipe in core, then it means we'll be blocked on removing install profile support from core until it's fully implemented in Drupal CMS, which could be another couple of years potentially.

Good point, I think the default site templates planned for Drupal CMS 2.0 would serve the same purpose in an updated way with Experience builder, etc. So at that point Umami is superseded already. Yeah. This would probably mean removing the install profile selection in 11.3 (2025 december) and deprecate Umami in core 📌 Deprecate and remove the Umami demonstration profile from core, make it a contributed site template Active at the same time?

I think 11.3 is reasonable timing. We won't be able to fully deprecate install profiles until we've added support for some of the things distributions can do to site templates, but it would be good to be able to work towards it.

Should this also do this issue in 11.3 or in Drupal 12? I don't know what other contribs may depend on the install profile selector (ie. they would come with multiple install profile selector).

I think the installer batch steps and form structure are something we can change in a minor release, if a distribution is shipping multiple install profiles in a single distribution, they would be able to add the page back again (if they're not already replacing it entirely).