I often see ce qui and ce que where I would expect to see qui or que. In these cases, the sentence still makes sense to me, but I wish to understand it more exactly.
I need to go find better examples with which to later update the question, but for now all I have is this, and this is a very weak example of what I'm talking about:
Tout ce qui brille n'est pas or.
I would have expected tout to be the noun, and for it to read as tout qui brille...
Here is a better example:
Ils avaient entendu dire que Malefoy resterait aussi, ce qui leur avait semblé particuliérement louche.
I would have expected qui, not ce qui.