To continue to discussion here, in cases where code splitting:

1. Uses a small number of chunks (say just two layers at most)
2. Does not use dynamic import at all

it could be beneficial to have UMD / IIFE support for code splitting.

Chunk global names can be based on the chunk name, and similarly for entry points. The tough part then is just ensuring the script order, but this information is available as the output of both generate and write.