Options provided only at the launcher level — usually flags that must be processed before starting the JVM — are not included in --help output. This effectively makes them hidden options. Several of these would be useful to include in --help:

• --environment helps debug configuration issues preventing JRuby from launching.
• --cache and related flags are used to work with AppCDS archives on supported JVMs.
• --checkpoint is used by the experimental CRaC subsystem.

I'd like to find a way to get these launcher options into the --help output. My idea at present would be to have a file in bin that provides at least documentation for these issues (so it can be read and included by the --help formatter) and potentially provides the actual implementation of these features (to allow us to start modularizing these features rather than having one giant shell script).

Modularizing may be out of scope for this issue, but I think it's worth some discussion. Nearly every one of these flags are associated with a "plugin" or "feature" of the launcher.