The "Root cause of XS-Leaks" section is a bit hard to understand

[arturjanc]

I've been thinking about proposing some updates to the "Root cause" section, but I'm having some trouble understanding the main points it tries to convey. Basically, it starts by describing how XS-leaks are inherent to the design of the web (which makes sense), but then it switches to cover defenses and tries to propose a categorization of XS-leaks, which aren't directly related to the root causes.

I think the few initial sentences about how XS-leaks are caused by the design of the web are already covered by the Overview section above, so they may be redundant and we could remove them here.

If we do so, maybe we could rename this section to something like "Attacks and Defenses"? Then, the bullet points at the end of the section could form the attack part (and we could link to some more pages about individual attacks), and the second half of the first paragraph ("For this reason, browsers are now implementing various Defense Mechanisms") could follow with a link to the high-level defense article.

This way we'd also give the reader a better flow for exploring the rest of the wiki.