英語版 (Eigo-Ban, "English version") refers to a book, music, film or any other work in English, implying that it is also available in another language which, in the Japan-based Nico Nico Douga, is usually Japanese.
This is a relatively popular keyword, tagged onto over 700 videos in Nico Nico Douga (as of March 2018). The tag "English" is often used in the same sense. Add to that specialized tags like "英語で歌ってみたリンク (Links to songs sung in English)". We have quite a number of English versions here. But why?
The majority are works originally composed in Japanese: Animes and their theme songs, video games or even Vocaloid tunes. Viewers tend to know them already in their mother tongue, yet there are good reasons to tackle with the alien language.
First of all it would make English less alien. One can infer the nuances in difficult vocabulary or complex expressions with the aid of their favorite piece, and make them their own through the experience.
On the other hand, there are those who enjoy the difference; it could simply be for fun, or because it's cool. Yeah, English sounds cool indeed for many of us, and often it doesn't matter what it means. Teiuka dosakusani magirete tekitouni Nihongo tsukattemo barehen kamone. Sometimes there's more than what words can convey.
Of course there are cases when English is the original language. Then you might want to check it to see what may have been lost in translation. Sadly too often, Japanese translations (including film subtitles) are so awful that critics comment with irony: "The English is much more comprehensible!"