Define the 3 areas the Top Bar will provide

Working on the definition of the 3 new areas.

plopesc → changed the visibility of the branch 3484564-define-top-bar-regions to hidden.

plopesc → changed the visibility of the branch 3484564-define-top-bar-regions to active.

Initial round to define the new TopBar render element and the plugin system to define top bar items.

We can iterate from here if the approach is considered valid.

Conceptually I don't see an issue. The fact that it's not editable makes sense.

on the PHP implementation i'm not the best person to comment, just pointing out that the region names feels a bit magic, if we're really tryin to enforce the 3 areas i'd use an enum or something a bit more restrictive (and maybe easier to document).

As it is contrib can add anything fairly easily, and i'm not sure it's a feature or not.

Good point about the enum!

Created and used it as part of TopBar::preRenderTopBar() . Tried to use the enum in the twig template as well, but it was not possible, given that enum support in Twig has been added recently and will not be available until 3.15. Core is now using Twig 3.14.

See https://twig.symfony.com/doc/3.x/functions/enum.html & https://github.com/twigphp/Twig/pull/4352

Regarding the styles, some basic styling is needed. Hopefully a more experienced FE dev could help here.

Let's get some minimal styling going on. just some barebone flexbox layout to replicate the positioning we can see 📌 [PP1] Show entity information on the Top Bar Postponed

This issue has POC with styles required
https://www.drupal.org/project/drupal/issues/3401826 🌱 [PLAN] Top contextual bar Active

Left a (slightly drive-by) review on the MR.

I tried applying the patch today to see what functionality is being added. Unfortunately, The patch is failing to apply.
Navigation.module seems to be having conflicts.

Tried out the MR, This seems to be a solid way of defining the top bar elements. Thanks @plopesc!

I'm not really sure how to apply styles to nothing :)

Could you please add some test cases?