We added a bunch of user actions, that would keep the sequence tidy, but since we would have no option to show them at all, we have to wait until optional filtering is supported by the sequence visualisation tool.

There is an existing CL implementing most of it: https://codereview.chromium.org/2873373002/

List of the user actions we worked on in the context of Zine: https://docs.google.com/spreadsheets/d/1I5-p_WCQJxVv-OK3BXyGQ9McjGsUOvr7Er454zzcqp0/edit?pli=1#gid=1383506007