TYPO3 Core

Commit ba2386e7305e0d6e64db5cc485bc38728728ad8e https://review.typo3.org/26675 must be reverted - it destroys Extbase operability under the following criteria:

• Editing any record (pid is not set).
• Using any BE module that does not use the page tree.

Before, Extbase would look for the first root template. Felix removed this behaviour completely, replacing it with a raw $_GET['id']. This should be considered a HUGE breaking change for any third-party Extbase extension that operates in the BE without using a page tree. As such, it should not be allowed in the LTS.

Core extensions are not broken by this simply because they abuse the ext_typoscript_setup.txt pattern to load (massive) amounts of TS that cannot be controlled.