The city charter, Denver's constitution, is pretty sacred. The document lays out a whole slew of things, from what the city considers a nuisance to when city council can meet.
The latter is where 2F comes in.
What the ballot actually says: Shall Article III, Part 3, of the Charter of the City and County of Denver be updated to remove outdated language and allow for modernization of the conduct of city business?
What the ballot actually means: In short, if you vote for this ballot measure you'll make it easier for city council to call meetings. You, the public, would still be given 24 hour's notice of when the meeting is to occur. The measure would also allow city council and the mayor's office to address outdated language in the city's charter.
Who supports it: City council does. The mayor is neutral on the ballot measure.
Who's against it: No one formally, and no one informally, at least not publicly.