I think the article was making the point that someone debugging a HTML page would do well to look at both "Inspect Element" and "View Source," as there might be

I think the article was making the point that someone debugging a HTML page would do well to look at both "Inspect Element" and "View Source," as there might be errors only visible in the latter. For example, a few weeks ago, I was testing a website. It worked fine in Firefox, Chrome, and Safari, but broke horribly in Internet Explorer. A look at the source made me realize that a syntax error in my templates was causing the first few lines of the source (including <html><head>, etc.) to render. The other browsers all ignored this.