Implement 'which'

[blee]

confman 'which' can be used to determine whether a file is managed by confman. If it is, the command should report information regarding the file, e.g. which module it came from or the singularity pieces used to construct it.

This information should also be exported to system utilities that will not have working copies. This can be accomplished, for example, with a locate-style database that is regenerated on every commit/sync operation and modified during install operations. There would be a corresponding 'confwhich' utility to access this information.