[ VKontakte Optimizer ] - The NEX (Opera 15+) [для разработчиков]

Опера поддерживает новый формат расширений NEX на основе хромовского CRX, над которым норвежцы активно работают и продвигают в массы.

Цитата:

Here we introduce NEX - a vendor-neutral packaging format for browser add-ons that we have initially implemented on top of the Chromium .crx format in Opera. We intend to further develop this as an open add-ons format through international standards bodies. Initially we intend to consolidate the differences between add-on execution environments themselves considering their current similarities. As a secondary objective we then aim to kick-start meaningful discussion around shared system and device-level APIs with a view to making browser add-ons first-class citizens of the web core.

Кто занимается расширениями или просто интересно вот документация NEX documentation