Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GT 630M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 391.35
I think this is broken since the late search bar (hit space, its an option when you first startup a new blender version).
Short description of error
Mesh relax, an inculded addon is not found/recognized.
Exact steps for others to reproduce the error
Using the latest blener i have spacebar search configured, it cannot find the relax addon, which also cant be added as a addon.
I dont think it should be installed its there allready (2.90\scripts\addons\mesh_tools ) in the proper folders allready, its just not seen by the program..