I was trying to look at the contents of an old file in subversion today that had long ago been deleted, with no luck. In the Eclipse plugin for CVS, they had a feature that would allow you to define a date, then browse the repository based on that date, but it seems to be missing from subversion.
I found a workaround, but it isn’t quite as nice. You can browse a specific revision of the entire subversion repository, then look at the file. All you have to do is go to this URL:
Where the base URL is the root of your repository, and the extra stuff after the ! specifies the revision. And don’t ask me what bc stands for, I have no idea.
As for finding out which revision to look at, that is a little tricky. It can be helpful to look at logs of other files and see which dates correspond to which revisions.