Operating system: Linux-5.8.0-7642-generic-x86_64-with-glibc2.32 64 Bits
Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.56
Broken: version: 2.93.0 Alpha, branch: master, commit date: 2021-03-23 07:34, hash: rBec97450ac616
Short description of error
Every preset is duplicated, one with uppercase, one with lowercase.
Exact steps for others to reproduce the error
Open any preset anywhere in Blender: They are duplicated. At least here, with factory-startup.