Without php-json extension Wordpress 5.3.2 fails during a fresh install with the following in Nginx error log:
[error] 9437#100173: *5 FastCGI sent in stderr: "PHP message: PHP Fatal error: Uncaught Error: Call to undefined function json_decode() in /usr/local/www/wordpress/wp-includes/class-wp-block-parser.php:232
#0 /usr/local/www/wordpress/wp-includes/blocks.php(521): WP_Block_Parser->parse('email@example.com')
#1 /usr/local/www/wordpress/wp-includes/blocks.php(274): parse_blocks('firstname.lastname@example.org')
Also, with php72-json installed it suggests a password during install and warns against weak passwords. Without php72-json it just asked for the password twice. There are probably more differences later.
This post has more details: https://make.wordpress.org/core/2019/10/15/php-native-json-extension-now-required/
thanks for the PR. I'll put that in the next wordpress update. Then all wordpress ports have to be adjusted here