src/admin/class-papi-admin-ajax.php
public function get_entry_type() {
		$entry_type_id = papi_get_qs( 'entry_type' );
		$entry_type    = papi_get_entry_type_by_id( $entry_type_id );

		if ( empty( $entry_type ) ) {
			$this->render_error( 'No entry type found' );
			return;
		}

		wp_send_json( $entry_type );
	}
public function get_entry_type() {
		$entry_type_id = papi_get_qs( 'entry_type' );
		$entry_type    = papi_get_entry_type_by_id( $entry_type_id );

		if ( empty( $entry_type ) ) {
			$this->render_error( 'No entry type found' );
			return;
		}

		wp_send_json( $entry_type );
	}
Get entry type via GET.

GET /papi-ajax/?action=get_entry_type