Disclaimer: This information gathered in this post is not an official announcement from Firaxis. It is obtained from data mining from xml files of Civilization VI after every major update, which may or may not reflect future contents. Only read this blog post for information and discussion purposes.
As many of you know, after the July update (concurrent with the Ethiopia Pack), the new civilization and new alternative leader for the Pack 5 (January 2021) were hinted to be Vietnam and Kublai Khan. These choices are not surprising, considering the civilization choices made in NFP were largely influenced by polls on the CivFanatic Forum, which were published a few months after the release of Gathering Storm (as the matter of fact, the only popular request currently missing is the return of Portugal). Vietnam and Kublai led their respective polls about "New Civ to the franchise" and "New alternative leader".
In the new Teddy Roosevelt folder in the DLC folder in game data, there is a readme which states:
This folder contains gameplay data. Be careful to distinguish between two types of gameplay files:
1. Gameplay that needs to be on by default (ex. KublaiKhan_Vietnam_Civilizations.xml for the new content, KublaiKhan_Vietnam_Expansion2.xml for tweaks specific to playing in the XP2 ruleset) Expansion1_Required Material will work in either expansion as long as you have Expansion1 enabled.
2. Gameplay that is part of an optional mode, specifying the ruleset needed (if any) and ending in “_Modes” (ex. KublaiKhan_Vietnam_Modes.xml for content related to the Alternate Economy game mode)
https://forums.civfanatics.com/threads/ethiopia-pack-patch-notes-discussion.660949/page-4
This readme was quickly deleted the same day.
Trung Trac was initially predicted to be the leader of Vietnam, since we only have 1 female leader in NFP so far, and the whole reason why Vietnam is so popular is due to a Civ5 mod, where Vietnam was led by both Trung sisters. However, this chance is slim after Trung Trac was introduced as a Great General in November.
Regarding the tentatively named game mode called "Alternative Economy", we also know a few things, regarding concepts like Monopoly, Industry and Corporations:
- This is from the September (Byzantium and Gaul) update:
"CREATE TABLE "Improvements_MODE" (
"ImprovementType" TEXT NOT NULL,"Industry" BOOLEAN NOT NULL CHECK (Industry IN (0,1)) DEFAULT 0,"Corporation" BOOLEAN NOT NULL CHECK (Corporation IN (0,1)) DEFAULT 0,"
- This is from the November (Babylon) update:
From the Global Parameters:
<Replace Name="MONOPOLY_REQUIRED_RESOURCE_CONTROL_PERCENTAGE" Value="75" />
<Replace Name="INDUSTRY_NUM_REQUIRED_RESOURCES" Value="2" />
https://forums.civfanatics.com/threads/industries-and-monopolies-are-coming.664767/#post-15963333
P/s: How accurate can these things be? If you think the November game mode leaks were known only 3 weeks before the release of Babylon, we actually knew it a lot sooner than that. Below is a thread in September, after the release of Byzantium and Gaul, regarding a new unit class called Hero, including information about Hero abilities of Maui, Sinbad, Beowulf, Arthur and Hippolyta in great details, and the methods of discovering Heroes. Also in this thread, the Pirate scenario, which was supposed to be released 1 month later, was also found way ahead of time:
https://forums.civfanatics.com/threads/speculation-possible-game-mode.663125/