Just seems like an odd choice of terminology, given that "rewind" implies going backwards in common usage. What's wrong with the more common "rewind"/"fast forward"?
Agreed. To rewind is to wind back. Rewind back is logically equivalent to forward, although our poor monkey brains (http://itre.cis.upenn.edu/~myl/languagelog/archives/004716.html) have many issues with multiple negation.
For distinguishing the terminology from Opera as well as starting with the same word, a possible alternative might be:
Some phrasings/wordings present in Otter can be called outright Polishisms, the same way as those in Opera were Scandinavicisms. Not that these things are bad in themselves. Even original American terminology differs. There's Unix terminology, Microsoftisms, Applespeak, Googletalk, etc.
Still, some guidelines seem to be inevitable. The default language is English, obviously. Between different terms present in different browsers, I think Opera (up to v.12) should take preference, because that's the one Otter is explicitly emulating. Any other choice should only apply if Opera's term is a screaching Scandinavicism or the other choice is overwhelmingly and indisputably more widespread, established and more descriptive. No need to reinvent the wheel in any case.
Rewind and Fast Forward always felt nice and dandy for me, directly borrowed from tape recorder terminology. They were apt also in the interface, because Fast Forward was a longer term and, when the button displayed the text, it was a huge button that invited to be tried out. In tape recorder you knew what was going to come when you fast-forwarded, but with Opera it was exciting, so it was appropriate that the button was huge :)
@ersi, true, I've changed them to how it was in classic Opera.