[Policy] Move book to contrib in Drupal 11

Removing a thing from core requires signoff from all the committer roles, as well as an opportunity for the subsystem maintainer to provide feedback if there is one. That is @pwolanin in this case. I spoke with @pwolanin about this previously was something along the lines of "But what about hierarchical things?" and "Meh, okay". It would be good for him to give his own answer here, though. :)

The committer team recently reviewed our scoring exercise on all core modules. There is a reasonably strong consensus that Action is neither a foundational capability nor strategically valuable to the product roadmap, so it should be removed. I am marking RTBC, but leaving the tags on to give committers a chance to confirm that they agree.

Myself, @catch, @quietone, and @longwave all agree on moving Book to contrib.

From a framework manager point of view, I'm happy for it to be moved to contrib. There are contrib solutions like entity hierarchy (disclaimer, I'm a maintainer) that have support for other entity-types, multiple hierarchies and drafts.

Moving book to contrib will hopefully unlock velocity.

Not removing the tag as giving others a chance to chime in.

I am removing the 'Needs subsystem maintainer review' tag because pwolanin (listed in MAINTAINERS.txt as the maintainer of the book module) agrees with moving Book to contrib.

Sad to see this go because along with taxonomy module it was one of the two features that got me involved in Drupal in the first place.

However, I use taxonomy on 99.9% of sites I'm involved with, and book module on exactly one site that was first installed in 2005 (exactly two sites if you include Drupal.org, which is a bit older than 2005), so it makes sense for it to live in contrib and/or eventually for there to be a migration script to a more generic solution like entity hierarchy. Removing the framework manager tag since @larowlan already signed off too.

No objections to remove it from core and hopefully have it prosper in contrib. As Gábor points out, an important part of what it does is already achievable with core menus. What Book adds to that in management and outlining have a very clunky UI that has received very little attention over the years.

I wanted to think that paging through a hand-picked selection of things (entity queue?) is in itself not an uncommon use case. There's even a Paging category → for contributed modules, but a quick look at usage numbers there shows numbers from 3000+ installs then tapering of quickly and mostly for older versions of core.

Two product managers @Gábor Hojtsy and @yoroy agree to the removal of Book. Both @xjm and I agree that the 'Needs product manager review' tag can be removed.

Thanks to everyone for commenting! This now has approval, and sign off from the various managers. I am marking this fixed.

We probably need to open an implementation issue now, I don't think one was created earlier.

Never mind, found it :) 🌱 [Meta] Tasks to deprecate Book module Active

Automatically closed - issue fixed for 2 weeks with no activity.