Multi-tab selection
At some point of Quantum development, Firefox introduced the ability to select multiple tabs via shift / control. It would make a lot of sense for Tab Center Reborn to mirror this feature, if feasible: it would match the design/behaviour of the native tab bar, like this add-on aims to and generally does; multi-selection is also very useful for reordering, closing and bookmarking, which fits the use case of managing large amounts of tabs.