Do not strictly compare values when determining whether to save or not in `DC_File` (see #7016)
Remove the example website from the core distribution

The example website is now available in the extension repository.
Try to raise the PHP limits upon file synchronization (see #7035)
Back port the changes from c2504021b7b3dc7f5daef8e0ffc736c2dd3e285b
Back port the changes from 0ed907b7e297b376a28a1057b7cd0639a92e93f3
Back port the changes from 40aa1084bada1af63078f624cd94d7b6fd26f013
Back port the changes from d8269c7cb85c7d78a29c5aa9c9acc03a266684f1
Back port the changes from f4f678264021ed86e9bba57854cc9346ce6a3f62
Render all root nodes in the page and file picker (see #6844)
Back port the changes from 27e76f7737e1159a077144eeb50e04087b87def8
Back port the changes from 6917fff2a0271e6306a6343712b8add70855d8da
Convert image source insert tags in the back end preview (see #7065)
Fix the phpDoc example code of the `Session` class (see #7069)
Disable the debug mode in the extension creator (see #7068)
Return `$target` in `Image::get()` if a cached file is copied
Also check whether to resize an image if `$width` or `$height` are omitted
Add the media query to the style sheets in debug mode (see #7070)
Back port the changes from 0c72ed00864fbfeada410b6ecb57f143e2f515fa
Only show the sort hint if there is more than one element (see #6935)
Colorize links in the back end preview (see #7027)