Rated 3 out of 5 stars

UPDATE:
Actually, Ublock Origin now implements :has() and :xpath() filters, starting from version 1.8.0.

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Advertisers are progressively moving away from banners and explicit ads towards sponsored content sneaked into your articles, feeds and streams.

With the popularity of ad blockers based on CSS, web designers are stripping adverts of their identifiable CSS attributes, effectively making this type of filtering obsolete.

Xpath expressions let you block element with much more flexibility.
For example if you want to block the sponsored tracks on Soundcloud, you can select them by some part of their «Sponsored Track» header.
It looks something like this:
//li[@class='soundList__item'][div/div/div/span[contains(@class,'sc-promoted-icon')]]

Currently though, it doesn't work in multiprocess mode.
I really hope the dev can manage to upgrade it before Mozilla rolls out e10 into the standard Firefox version.