> Local-first was the first kind of app. Way up into the 2000s, you'd use your local excel/word/etc, and the sync mechanism was calling your file annual_accounts_final_v3_amend_v5_final(3).xls

To be precise, these apps where not local-_first_, they where local-_only_. Local-first implies that the app first and foremost works locally, but also that it, secondly, is capable of working online and non-locally (usually with some syncing mechanism).

That sync mechanism was called save to floppy and hand it to whoever you want to share your changes with.