Don’t let the notion of “editorializing” throw you. What he is speaking about is Mark constructing his account to show context and connections. This analysis is part of a method which is subjected to literature and the author is including the section as part of this investigative method. Tradition has it that Mark used Peter’s preaching Jesus in composing the account for the Romans who wanted a written record of this good news. Christians know that God the Spirit is the ultimate author of the bible.

Copper Coins, Catchwords, and Contextual Cues: The Climactic Placement of the Widow’s Mites (Mark 12:41–44) — Tyndale Bulletin