Hi,
The form cit0007e titled Document Checklist Application For Canadian Citizenship.... is a mandatory checklist that you must attach in your application package.
This form(cit0007e) has two sections, the top section has a list like Application for citizenship ( CIT 0002), Physical presence calculator, Photocopies of biological pages of your passport, Language requirement, personal IDs like driver's license, health card, PR card etc. The documents in this list are mandatory and are to be made available with your application package.
The lower section of the form(cit0007e) is case specific and hence will be optional for some people like Photocopies of Name Change, Date of Birth correction, Original PCC, IMM5476, cit0177 etc.
Hope this clarifies the doubt.
All the best with your processing.