This list describes what features of the Companion Module API is implemented in buttons.
Core This feature will be solved outside of the modules, and will be handled by the buttons core instead. This might break some implementations that works in companion, but will put less responsibility on the modules in the end.
SetCustomVariable
This api call will not be supported in buttons due to it working against the reusability of connections. Connections can declare their own variables, and custom variables can inherit or use those values if needed, in workflows.