We've been thinking about this as well. The reason we don't currently expose the id used internally by the project database is that this id is only unique for the given database file, but we'll be exploring different ways to incorporate additional ids.
Our aims for this are a) to automatically generate useful ids which are easy on the eyes b) allow the ids to be changed to support external identification systems.
At the moment your options are not great, but you could use the
dc:identifier property to add your own ids (but they are not populated automatically. To see Tropy's internal ids in SQLite you could run a query like this:
select id, text from metadata join metadata_values using (value_id) where property = 'http://purl.org/dc/elements/1.1/title';
This would print all item ids and titles side by side.
You could also read out the ids in Tropy using developer mode (needs to be enabled in the preferences). Select
Developer -> Toggle Developer Tools from the menu. Then select an item in Tropy whose id you wish to see. Then, in the
Console tab of the dev tools enter:
state.nav.items to see a list of all currently selected ids.