There are active effect keys for automatically failing ability checks, saving throws, skill checks, and casting spells. Only keys relavent to saving throws are supported. The choice to only fail saving throws was made because those are the only auto-fail rolls that the base rules support. However, if there is a use case for adding support for other checks, they can be added.
If the player holds down one of the Ctrl/Alt/Shift/Meta keys to fast-forward the die roll (e.g. hold Alt to roll with advantage, skipping the roll dialog) then this module WILL NOT do anything. Holding down one of those keys stops the roll dialog from popping up so it's interpreted as overriding what this module does.
In addition to active effects adding advantage or disadvantage, you can also add messages to remind you of conditional bonuses or advantage. For example, features like Dwarven Resilience give advantage on saving throws against poison don't work with the advantage flags since there isn't a way to limit it to poison. Now you can add a message to the dialog right above the buttons to remind you about Dwarven Resilience.
Messages has more information about the messages feature, including the active effect keys.
There are some compatibility issues with other modules that change the default dnd5e die roller. If you use one of these modules, follow the Project URL link to get the latest information.