This uses a new feature which is available since PHPCS 3.x.
The effect will depend on the system on which PHPCS is being run, but if parallel processing can be run, the build should be faster using this option.
The `-n` flag will ignore warnings completely, while often it is useful to see them and to fix them.
Using `--runtime-set ignore_warnings_on_exit 1` in the Travis script instead, warnings will be shown, both when a developer runs PHPCS on their own machine, as well as in Travis, but warnings will not cause a failed Travis build.
The `-v` flag will list each file being scanned. This is intended for debugging purposes and not needed for normal use.
The link was pointing to the `WordPress-Core` ruleset, while `_s` uses the `WordPress` ruleset which encompasses more than just the core rules.
Pointing to the repo + the wiki seems more appropriate to me.
If the file is called `phpcs.xml` or `phpcs.xml.dist`, it is automatically picked up by PHPCS.
A `phpcs.xml` is given preference over a `phpcs.xml.dist` file. So renaming the file to `phpcs.xml.dist` allows for people to use the file provided by `_s` if they choose not to add their own, but also leaves people the freedom to easily overrule it.