The spoiler-y things about Extra!Rin the anon was talking about, is probably about her heritage. There was one person who claimed her to be the product of an European affair Tokiomi once had, but it is more widely known and accepted that she is the child of Sakura (which if I recall right you have been told about once already). I can't really think of anything else about her that would be regarded as spoiler-y.
Ohhhhh. Unless that information about Extra!Rin impacts on the direction the story takes, I wouldn’t really regard it as spoiler-y. But thank you for clearing it up :3
And omg though, I wasn’t aware that the idea that she’s Sakura’s child is more accepted and well-known (though it would be really easy to make that link). Somehow, I actually prefer the idea that Tokiomi had an affair, and I have no idea why. XD