is calculated at build time. SRI checks whether the files you deployed are the ones you are getting. If it's different, it won't run. Your site might break, but your customers are safe.
the browser from which hosts it can load things. You tell it to only trust the domains you are expecting: Your CDN, tagmanager.google.com, etc. When used properly, it makes XSS much more difficult.
full migration to JS components, rather than inline calls to require(). Add a configuration field for allowed hosts. Send it as a header in every request.