This can include any number of documents, such as editorial introductions, critical essays, bibliographies, etc. 

5. Glossary of Spelling and Capitalization

G. Glossary of Spelling and Capitalization

This glossary records Thackeray's spelling and capitalization practices for words and phrases in the copy-text of Catherine in cases where the copy-text's forms are unusual, inconsistent, or different from Thackeray's characteristic forms. In addition, the entries that follow contain, where possible, discussions of the usual forms found in Fraser's Magazine; and in all cases a suggestion is made as to whether the copy-text form is likely to be authorial.