The following hotkeys usually combine several interactions into one. They exist as quality-of-life features towards users.
Filters your selection based on tech. All engineers that are of a lower tech assist the higher tech engineers.
Loads all transportable units of your selection into the transports of your selection. The implementation prefers to use higher-tech transports and prefers to load higher-tech units first. The implementation prefers to fully load a transport. Not all transports are necessarily used.
Units are loaded in three stages:
This is intentional. Due to an engine bug, the transports may assign tech 1 units to slots that then end up blocking tech 3 units. It can negatively impact the time that it takes to load the transports in comparison to other methods.
Cancels the navigation of the engineers in your selection. A lot of orders have a navigational element in them. For this example, we'll take the assist order. The unit will first move in formation around the target that you intend to assist. Usually, this is a lot closer to the target than what is technically required. Using this new hotkey you can manually abort the navigation and immediately proceed to apply the order.
The same applies to any order with a navigational element to it. Specifically, it is interesting for the build, reclaim, capture and attack move orders.