1 # static mixed http\Env::getResponseHeader([string $header_name])
3 Get one or all HTTP response headers to be sent.
7 * Optional ```string $header_name```
8 The name of the response header to retrieve.
12 * ```string```, the compound value of the response header to send
13 * ```NULL```, if the header was not found
14 * ```array```, of all response headers, if $header_name was not specified