These changes are important enhancements for both accessibility Accessibility (commonly shortened to a11y) refers to the design of products, devices, services, or environments for people with disabilities. The concept of accessible design ensures both “direct access” (i.e. unassisted) and “indirect access” meaning compatibility with a person’s assistive technology (for example, computer screen readers). (https://en.wikipedia.org/wiki/Accessibility) and user experience on small screens.
Block Block is the abstract term used to describe units of markup that, composed together, form the content or layout of a webpage using the WordPress editor. The idea combines concepts of what in the past may have achieved with shortcodes, custom HTML, and embed discovery into a single consistent API and user experience. styles use relative instead of absolute values
Previously, blocks were using hardcoded pixel values for all their sizing properties (paddings, margins, font-sizes etc).
Starting with WordPress 5.6, default block-styles use font-size-relative units (
em) making it easier for themes to change the default content font-size without having to rewrite/override all block styles.
Media & Text blocks show media on top in mobile view
Previously, if the stack on mobile behavior was not disabled, and media had the option to appear on the left (the default), on mobile, the media appeared on top and the text on the bottom. If media had the option to appear on the right on mobile when stacked media would appear at the bottom and text on top.
There was feedback that the left/right position of media should not map to top/bottom on mobile and that for a better UX User experience on mobile, media should always appear on top. Starting with WordPress, 5.6 media text blocks will have media on top on mobile unless the stack on mobile option is disabled, and in that case, media appears at the side of text like on desktop.
Props to @aristath and @jorgefilipecosta for writing these dev notes Each important change in WordPress Core is documented in a developers note, (usually called dev note). Good dev notes generally include a description of the change, the decision that led to this change, and a description of how developers are supposed to work with that change. Dev notes are published on Make/Core blog during the beta phase of WordPress release cycle. Publishing dev notes is particularly important when plugin/theme authors and WordPress developers need to be aware of those changes.In general, all dev notes are compiled into a Field Guide at the beginning of the release candidate phase..