How to pass query parameters in URL in Salesforce Summer 19 Release?

I think there is a Critical Update that gets auto-enabled for Summer '19, that forces Lightning URL parameters to be namespaced. And the default namespace for orgs is "c".

So if you add ?foo=bar to the URL, it will get auto-stripped.

But if you add ?c__foo=bar to the URL, it will persist.

Here is the Salesforce critical update that talks about this.