mkdir protonaospcd protonaosp
Then initialize the folder and sync the source code:
repo init -u https://github.com/ProtonAOSP/android_manifest -b rvcrepo sync
This is a large download that will take approximately 100 GB of disk space, so plan accordingly.
If it’s too slow and you have a fast internet connection, you can try downloading with multiple connections in parallel:
repo sync -j8
rvc: Android 11 (Red Velvet Cake)
See Build for instructions to build the downloaded source code.