We stopped rendering AdminNotices compatibility component, as this previous attempt at backward compatibility was bringing in numerous incompatible banners and notices from plugins.
An update to the parser to better deal with malformed HTML that could cause a loop. We’re only aware of this in the wild being triggered once in the over a million posts made with Gutenberg, but it caused a loop so we wanted to fix for RC2.
Cosmetic and minor changes in RC2
Accessibility: Simplify sidebar tabs aria-labels.
Make the Image Link URL field readonly.
Internationalization: Merge similar text strings that differed only in capitalization.
CSS: Improve block preview styling.
CSS: Fix visual issues with Button block text wrap.
Fix getSelectedBlockClientId selector.
Fix Classic block not showing galleries on a grid.
Fix an issue where the block toolbar would cause an image to jump downwards when the wide or full alignments were activated.
Move editor specific styles from style.scss to editor.scss in Cover block.
Fix modals in Microsoft Edge browser.
Fix Microsoft IE11 focus loss after TinyMCE init. Add IE check.