New plugin - can't get $_GET parameters

I’ve just created a new plugin, following the tutorial with the command bin/plugin devtools new-plugin. My goal is to read the GET parameters given with the URL and the output the result on the page.
Example: When I type in my browser, I want to read the values. Normally I can do that with $_GET['name'] and $_GET['email']. But the $_GET variable only has one value: $_GET[_url].
My plugin subscribes to the onPageContentRaw main event after checking the route, as shown in the tutorial. I simply changed one line to see if the values are present:

$e['page']->setRawContent("Dump of _GET: ".print_r($_GET, true) . "

" . $content);

Can anybody help me to understand, what I’m doing wrong? I thougt is, that $_GET and $_POST are global in every PHP script.

Thank you very much.

you may have a scope problem. Try to put this line before your dump:

global $_GET;