There are 3 tiers of data in config_lib.pasm /config.fpmc 

1) data that is useful at parrot runtime.

perhaps {{{has_icu}}} - these can go in config.fpmc and parrot_config.

2) data that is useful at extension or HLL build time:

perhaps {{{ccwarn}}} - these can go in parrot_config.

3) data that might be useful tracking down an issue for a parrot porter.

perhaps {{{configure_args}}}, *_provisional - these shouldn't be saved in parrot's config, but can be saved out in a build file for debugging. You shouldn't be able to see them in an installed parrot.