In WordPress 5.5, the core blocks continue to evolve with the addition of new block tools.
Custom Line Heights
Users can define custom line heights for headings and paragraphs. Themes can opt-in into this feature by defining the custom-line-height theme support flag.
add_theme_support( ‘custom-line-height’ ); Custom Units
In addition to pixels, users can now use other units to define the height of Cover blocks. The available units are: px, em, rem, vh, vw. Themes can opt-in into this feature by defining the custom-units theme support flag.
add_theme_support( ‘custom-units’ );
Themes can also filter the available custom