The default action is for the URL to be 'printed' (opened) in the browser, unless `viewer` is specified as something else. If `viewer = NULL`, then the URL is printed as a character string.
# S3 method for inzHTML
print(x, viewer = getOption("viewer", utils::browseURL), ...)
a URL that will be printed
the viewing function to use to display the URL
additional arguments
NULL (it's a print function, after all)