You might find the conversation in this thread develops in an interesting fashion, if I haven’t already mentioned it before:
This dates from a time when if you pasted code with ‘runlocally: true’ into the IDE, you would get a cryptic error as it wasn’t actually allowed for the community. Then suddenly it was. I always thought warning people about the error message would have been a more comprehensible solution.
Oh and my understanding is that the local handlers are part of the firmware download. So nothing dynamic is happening.