wp-includes/class-wp-block-processor.php:1658Returns the string content of a matched HTML span, or null otherwise.
string|null public function get_html_content(): ?string { if ( ! $this->is_html() ) { return null; } return substr( $this->source_text, $this->after_previous_delimiter, $this->matched_delimiter_at - $this->after_previous_delimiter ); }Introduced in 6.9.0. Unchanged from 6.9.7 through 7.1.0.
Signature, return type and hooks compared across 3 parsed releases.
src/wp-includes/class-wp-block-processor.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.