Today while documenting all the modules that we've removed from core in Backdrop CMS, I realized that we've also been removing a lot of other cruft that's making the system lean and mean. I'd like to document all that for you here (but mostly for myself, for future reference).
Here's the list of modules that have been removed from core:
- Aggregator
- Blog
- Dashboard
- Forum
- Help
- OpenID
- Overlay
- PHP filter
- Poll
- Profile
- RDF
- Shortcut
- Statistics
- Tracker
- Trigger
Database support
Drupal 7 boasted an enterprise-ready database abstraction layer, but in reality running anything other than MySQL turned out to be a real PITA since most Drupal code was written assuming a MySQL database and rarely tested against anything else. In Backdrop CMS, we removed support for databases other than MySQL or MariaDB. Removing support for alternate database backends means that we can add MySQL-specific database optimizations that will make backdrop even faster.
The theme system
Drupal 7's theme layer was also overly complex and very difficult to understand. In Drupal 8 we did a lot of work to remove different systems and simplify while converting everything to Twig. In Backdrop, we're also trying to simplify as much as possible while keeping everything the same. To this end, we've removed the Process phase from Backdrop (it came after the preprocess phase and before the template was used) and we've also removed the infamous hook_page_alter() function that allowed anything to be moved around on the page at the very last minute. Both of these theme system simplifications resulted in a performance gain.