is_https()

mb_strpos($haystack, $needle[, $offset = 0[, $encoding = NULL]])

get_mimes()

show_error($message, $status_code, $heading = 'An Error Was Encountered')

config_item($key)

array_replace_recursive(array $array1[, ...])

array_column(array $array, $column_key[, $index_key = NULL])

html_escape($var)

quoted_printable_encode($str)

array_replace(array $array1[, ...])