to unlock lucia content you must type "truestory" (without "") code in notepad in your in-game PC
That cheat code changes Felicity and Emma's relationship from clone to sister (twin, if I recall). Nothing to do with Lucia.
never heard of a cheat code changing felicity and emma relationship, to be honest I've found and actually used the code "truestory" to start the 2 Lucia events. I know the code because i'm in runey's discord and he specifically wrote it in the FAQs
Oh? Maybe it changed sometime in the last couple updates. I got my info from the FAQ too, bout a year ago, bit less maybe. Plus I can confirm it does change how Felicity and Emma talk; I clearly recall old save files where they said "Clone", after using the cheat, "Twin".