wp-includes/html-api/class-wp-html-processor.php:5875Reconstructs the active formatting elements.
bool private function reconstruct_active_formatting_elements(): bool { /* * > If there are no entries in the list of active formatting elements, then there is nothing * > to reconstruct; stop this algorithm. */ if ( 0 === $this->state->active_formatting_elements->count() ) { return false; } $last_entry = $this->state->active_formatting_elements->current_node(); if ( /* * > If the last (most recently added) entry in the list of active formatting elements is a marker; * > stop this algorithm. */ 'marker' === $last_entry->node_name || /* * > If the last (most recently added) entry in the list of active formatting elements is an * > element that is in the stack of open elements, then there is nothing to reconstruct; * > stop this algorithm. */ $this->state->stack_of_open_elements->contains_node( $last_entry ) ) { return false; } $this->bail( 'Cannot reconstruct active formatting elements when advancing and rewinding is required.' ); }Introduced in 6.4.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/html-api/class-wp-html-processor.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.