This proposal is to match de-facto usage in some CLI JS hosts that allow for Shebangs / Hashbang. Such hosts strip the hashbang in order to generate valid JS source texts before passing to JS engines currently. This would unify and standardize how that is done.
This feature is generally not intended to be consumed by the browser (rather, non-browser JS hosts) --- however, it potentially allows for a script with an interpreter line to run in the browser without modification, which could be seen as a benefit.
Interoperability and Compatibility Risks:
Ergonomics:
N/A, with the exception that we will want to make sure the web inspector knows how to process the interpreter line, so that it doesn't harm the debugging experience.
Activation: n/a