What were those? What I remember from Cello was that it was very simple. It just contained the bare minimum of functionality that a browser needed to support.

What were those? What I remember from Cello was that it was very simple. It just contained the bare minimum of functionality that a browser needed to support. I don't think there were any extras. It also had a very small executable size. I think it's correct that the name, at least, and maybe some of the functionality, was derived and inspired from Viola.