wp-admin/includes/class-wp-list-table.php:1381Returns the number of visible columns.
int public function get_column_count() { list ( $columns, $hidden ) = $this->get_column_info(); $hidden = array_intersect( array_keys( $columns ), array_filter( $hidden ) ); return count( $columns ) - count( $hidden ); }Introduced in 3.1.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-admin/includes/class-wp-list-table.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.