If we are talking about fholger/openvr_fsr, you should have copied over two files to the bin directory, openvr_api.dll and openvr_mod.cfg once a VR Session has been completed you should find a 3rd called openvr_mod.txt, for me initial test output was as follows
Initializing hooks...
Requested interface IVRSystem_019
Injecting GetRecommendedRenderTargetSize into IVRSystem_019
Requested interface IVRCompositor_022
Injecting Submit into IVRCompositor_022
Requested interface IVRExtendedDisplay_001
Creating post-processing resources
Input texture is in SRGB color space
Creating upscaled texture of size 2197x2155
Creating sharpened texture of size 2197x2155
Creating shader resource view for input texture 000001A14DD849B8
Texture has size 1472x1444
Mapping format 1c
Creating shader resource view for input texture 000001A14DD85438
Texture has size 1472x1444
Mapping format 1c
Shutting down hooks...