PAGE navigation does not support URL parameters. You need to perform URL navigation to make use of them. If you’re using PAGE navigation, you need to use the configured params from the Page Configuration for that page.
system.perspective.navigate(page = "/view/8")
URL navigation:
system.perspective.navigate(url="http://<GatewayIP>:<port>/data/perspective/client/<projectName>/view?key=8")
There is no documentation for URL parameter usage because it’s not an Ignition paradigm, but I understand why you’re asking. I’ll speak with the documentation team to see if we can add a bit about how to use the scheme in conjunction with Ignition parameters.