WP 5.8+
PHP Filter
Server-Side Design Tools
Add Custom Supports to Core Blocks
Enable missing design tools (like Line Height, Border, or Spacing) on Core blocks without modifying the block's source code.
Editor Sidebar Changes
Settings
Typography
Size Medium
Line Height 1.5
Border
Color
How to Implement
1
Identify the Block Name
Use the browser inspector or block documentation to find the namespace (e.g. core/quote, core/paragraph).
2
Paste into functions.php
Add the PHP snippet to your active theme's functions.php or a site-specific plugin.