The practice and procedure of "consent votes."
The aldermen and alderwomen consider certain bills to be uncontroversial after such bills have been reviewed by the appropriate committee and have received a recommendation from the committee that they be passed by the whole Board.
Such bills, when they are put to a vote for final passage, are grouped together on the "Third Reading Consent Calendar" of the official agenda. This signifies that the aldermen and alderwomen, by consent, agree that no further debate by the full Board is needed prior to final passage. If there is more than one such bill on the agenda during that meeting, the clerk conducts one roll call vote to pass several bills at once.
When that is done, such votes are said to be held "by consent," meaning that the aldermen and alderwomen have consented to vote without further debate and, if there are several such bills, to vote on multiple bills at once rather than have an up-or-down vote on each bill. Most votes conducted in this way are unanimous for passage.
If a single alderman or alderwoman objects to a bill's assignment to the Third Reading Consent Calendar, the bill is removed from the consent calendar, the bill can be debated, and the bill would be voted on in a separate up-or-down vote.