The "Eu" signifies the PAL version, which includes multiple European languages (English, French, German, Spanish, Italian).
You may be looking for a digital scan of the original printed instruction booklet (the "paper" manual) that came inside the Wii game case. Super-Mario-Galaxy-Eu-Nintendo-Wii.zip
The inclusion of the word in your search suggests you are looking for one of two things related to this specific file or game: The "Eu" signifies the PAL version, which includes