As I see, mappings are stored at user level, thus they are not transporable and not linked to the document. This is quite inconvenient, because this way it is not transportable, and if someone else is trying to work on a specific document, he/she has to recreate all mappings. Plus, as all mapping are valid in the same time it can be quite confusing. Over time the number of mappings can grow, so one will delete from them - ending up with missing mappings at a future point in time.
Why isn't mapping part of the document metadata?
I suggest a feature that enables saving mapping into the document file and importing it back.