Mojang have announced that they'll be making two of Minecraft's libraries open source soon, which means they're free for anyone to improve, mess around with or use in their own projects free of charge, with proper attribution of course.
The first Minecraft freebie library is called Brigadier and although the name doesn't ring a bell, if you've played the game - you know it intimately. We're talking about the underlying code that interprets and executes text commands in Minecraft's console.
"A lot of people think this is a really easy function [...] but the reality is actually extremely complicated", said developer Nathan Dinnerbone Adams. The code actually breaks up the command and tries to execute it, as well as suggest course of action once the slash key is input. As the devs put it, "you've got Brigadier to thank for all those sticks".
The Minecraft team are excited over what the community may do to improve Brigadier, since they're aware that most people shy away from console commands. What they're hoping for are ways to make it more user friendly though.
Data Fixer Upper is the name of the second Minecraft module that will sail into open source waters, although this library is notably more complex than Brigadier, deservedly so. Also, the name was apparently found so hilarious that the Minecraft team simply had to keep it.
What Data Fixer Upper does is convert older game data into what the modern engine can understand. Adams pointed out that if players fire up a level that's six years old, it first goes "through Data Fixer Upper and that turns it into what it should currently be now." This is basically the way Minecraft deals with older data, a problem Adams says all games eventually run into.
The Minecraft library announcement also revealed that Brigadier and Data Fixer Upper are only the first two libraries to be released as open source, with more to follow soon. Apparently, the team are considering releasing Blaze3D, "a complete rewrite of the render engine that [they]'re aiming to implement for 1.14."
You can find the official announcement here.