VIPs and other themes can declare the permastruct, tag and category bases in their themes.
This is done by filtering the option.
To ensure we’re using the freshest values, and that the option value is available earlier than when the theme is loaded, we need to get each option, save it again, and then reinitialize wp_rewrite.
On WordPress.com this happens auto-magically when theme updates are deployed
This function has no parameters.