Fatal error: Uncaught Error: Call to undefined function wp_get_block_css_selector() in /wp-includes/class-wp-theme-json.php:904
Stack trace:
#0 /wp-includes/class-wp-theme-json.php(607): WP_Theme_JSON::get_blocks_metadata()
#1 /wp-includes/class-wp-theme-json-resolver.php(562): WP_Theme_JSON->__construct()
#2 /wp-includes/script-loader.php(3232): WP_Theme_JSON_Resolver::get_merged_data()
#3 /wp-includes/script-loader.php(3428): {closure}()
#4 /wp-includes/class-wp-hook.php(308): {closure}('')
#5 /wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters(NULL, Array)
#6 /wp-includes/plugin.php(517): WP_Hook->do_action(Array)
#7 /wp-settings.php(645): do_action('wp_loaded')
#8 /wp-config.php(96): require_once('/wp-settings.ph...')
#9 /wp-load.php(50): require_once('/wp-config.php')
#10 /wp-blog-header.php(13): require_once('/wp-load.php')
#11 /index.php(17): require('/wp-blog-header...')
#12 {main}
thrown in /wp-includes/class-wp-theme-json.php on line 904