I’ve been trying to work out how to save attachments to a local database. Assuming this is not possible looking at the API, but there is not much documentation on the subject.
Found the answer buried in the REST API documentation:
Local documents are not replicated or indexed, don’t support attachments, and don’t save revision histories. In practice, they are used by Couchbase Lite’s replicator, as a place to store replication checkpoint data and can also be used to store temporary data locally (generally configuration or metadata).
Local documents are limited in what can be done with them (as you noted above). If you are looking to keep documents local so they don’t get replicated to the server, you can define a filter function on push replicator
This post should give you the details
“Local docs” are a weird holdover from CouchDB. I wouldn’t recommend using them. Version 2.0 will not have them.