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I agree with the others. Given "https://www.mysite.com/index.html is not currently displayed in search results", in all likelihood it is being redirected to https://www.mysite.com (and should be). So you don't want to change the canonical to the index.html version of the page only to have it redirected back to https://www.mysite.com. It'll unnecessarily slow the site and might even create a loop.