postface
/ˈpɒsfes/ or /ˈpoʊstfeɪs/Definitions
1. noun
A section at the end of a book, document, or other written work that provides additional information or commentary.
“The author added a postface to the book, discussing the historical context behind the story.”
2. verb
To add or provide a postface to something.
“The editor postfaced the report with a note on the methodology used.”