People (or maybe just dkg) have proposed various bits of user metadata to attach to messages - references to be added or blacklisted - encryption related key material Since such metadata would be not-reproducible from the message files, it would be "precious" and need a backup/restore path. This is a prototype of a library API to support that. Some things to note: - This is tested on top of my libconfig [1] series, but I think there is no logical dependency - there are no docs, see the tests - this is just the low level api; it would need to be extended in a similar way to the libconfig series to dump and restore metadata. This might require modifying/extending the API to dump all properties for a message. That should be a relatively small change. - it also be useful to be able delete all (key,value) pairs with a given key. - this should really go through the existing caching mechanism used by e.g. tags, or at least not invalidate that cache. [1] id:1463135893-7471-6-git-send-email-david@tethera.net