When browsing a project's source code at bitbucket.org/user/project/src, file URL's are of the form /src/HASH/filename.
I think it would be nicer if they defaulted to /src/tip/filename instead, since that is what most people look for when they browse code online.
Further more, such a link would be more useful to share with other people because it would not become outdated. Perhaps you could offer /src/HASH/filename as a perma-link option.
Thanks for reading!