This is a cover for the spool holder hole in the CC1, which will no longer be required if you have the Canvas.
This print replaces the existing holder using the original mounting points and screws. To install it, simply unscrew the old holder from inside the printer and replace it with this piece. 

I have added the wut emoji (by LaserVelociraptor) to mine, but you can easily customize it with your own designs by adding your own modifiers. 
The circle is 33.4mm in diameter, 0.8mm thick and centred on the model. I recommend having 1 more top layer than the number of multicolour layers to ensure the bridging is all done in a single colour. That will result in a much better top surface quality.