This repository is based on @tinytengu 's Repository
This is the source code of Minecraft's authlib 1.6.25 updated to 2.1.28 which you can use from Minecraft 1.16.5 inclusive (1.16.4 introduced social interactions so this library got changed to v2) both on the client and the server.
I don't own anything of this library, so if something happens, Mojang will sue you 🗿