The markles are currently implemented as such:
=={{edit separation|Page ###}}==
(### can be anything). This creates a thin black line and a small "edit" link enabling someone to edit just a particular page worth of text. In other words, it's a slightly tweaked "section" tag that does not display a title.
Here's a screenshot:

Once the project is "complete" (When Oni protects the page from anonymous editing, it's probably safe to say it's "complete") then the markers will be replaced with HTML style comments. This gets rid of the lines but keeps the page data.
I would like to add this to the Format/Style guideline as well, since it has vast potential to streamline the editing process.
Vote now!
=Smidge=