LineageOS is a free, community built, aftermarket firmware distribution of Android 11 (R), which is designed to increase performance and reliability over stock Android for your device.
LineageOS is based on the Android Open Source Project with extra contributions from many people within the Android community. It can be used without any need to have any Google application installed. You will need to provide your own Google Applications package (gapps). LineageOS does still include various hardware-specific code, which is also slowly being open-sourced anyway.
Base source code is available in the LineageOS Github repo. And if you would like to contribute to the project, please visit our Gerrit Code Review.
Formatting data (all user data is wiped, including internal storage) is a must if MIUI was previously installed and device was encrypted.
Credits & collaborations:
This work is due to efforts from Mi5Devs founding members (@h2o64 and me) that did the full device bring-up. Huge thanks to @deovferreira for all the help during the kernel bring-up after source code dropped. Last but not least, pleasure having @luca020400 and @LuK1337 onboard since the bring-up of the whole Xiaomi 8996 family.
Finally, all LineageOS team would like to thank everyone involved in helping with testing, coding, debugging & documenting! Enjoy!