This feature would work in a similar way to the Mustache Helper feature. Twig helpers could be installed via composer and they'd register themselves. Currently this is how the Mustache helper works:
install helper which gets registered
on load the helper is associated with a dispatcher event
when the pattern engine loads it fires the event and all helpers register themselves
The extension points have been added. Need to add the install feature to InstallerUtil in pattern-lab/core and update the types in pattern-lab/unified-asset-installer.
This feature would work in a similar way to the Mustache Helper feature. Twig helpers could be installed via composer and they'd register themselves. Currently this is how the Mustache helper works:
Example mustache helper.