[New API] Lists in config?

How can I read config lists like this?

Code:

example:
- ex1
- ex2
- ex3

What do you mean read?

It is not a list config. It is just a YAML. You just create a config object on that file and $config->get("example") to get a plain array equivalent to array("ex1", "ex2", "ex3"). But if you only want to save an array, you can consider creating config with Config::ENUM instead of Config::YAML, and
$config->exists("ex1");
$config->set("ex2");
$config->remove("ex3");

Thanks