Extra modules and utilities. Extras provide functionality that doesn't comfortably fit into the main Duktape library, perhaps for footprint or portability reasons, but are still useful for most users.
Extras are maintained and will be bug fixed. However, they don't have the same semantic versioning guarantees like the main Duktape library. Extras may be dropped without warning as Duktape is versioned. For instance, if an extra breaks due to Duktape changes and there is no time to fix it, the missing extra won't block a release and will be dropped.