I'm guessing they are planning everything. From the official minecraft article :
Now we’re actively working on Vibrant Visuals for Minecraft: Java Edition and our goal is to bring it to the game in a way that serves not only our players, but also our modders and resource pack creators.
Yeah it feels like they tried something different. With the first one, all the big ennemies were underlings of the Lady. Here, even though they inhabit the city (except for the hunter), they are not linked to the Thin man. It's a bit confusing.
But overhaul the game is still really good and scary. IMO being chased is one of the scariest thing, so stressfull.
I went into about:config
Restored browser.tabs.inTitlebar, to it's default value and then changed it to 1.
And when i restarted firefox the toggle option was back where it was supposed to be. O_o
It's actually a really good question. What you're explaining is called a collision, by creating the same hash with different numbers you can succesfully login.
This why some standard hashing function become deprecated and are replaced when someone finds a collision. MD5, which was used a lot to hash passwords or files, is considered insecure because of all the collisions people could find.
To be honest the official minecraft article contains more information and is in my opinion better written.
https://www.minecraft.net/en-us/article/minecraft-vibrant-visuals