You need to use the type with methodswith:
julia> using CUDAdrv
julia> dev = first(devices())
CuDevice(0): Quadro RTX 5000
julia> methodswith(typeof(dev))
[1] ==(a::CuDevice, b::CuDevice) in CUDAdrv at /home/tim/Julia/pkg/CUDAdrv/src/devices.jl:31
[2] convert(::Type{Int32}, dev::CuDevice) in CUDAdrv at /home/tim/Julia/pkg/CUDAdrv/src/devices.jl:29
[3] hash(dev::CuDevice, h::UInt64) in CUDAdrv at /home/tim/Julia/pkg/CUDAdrv/src/devices.jl:32
[4] show(io::IO, ::MIME{Symbol("text/plain")}, dev::CuDevice) in CUDAdrv at /home/tim/Julia/pkg/CUDAdrv/src/devices.jl:35
[5] attribute(dev::CuDevice, code::CUDAdrv.CUdevice_attribute_enum) in CUDAdrv at /home/tim/Julia/pkg/CUDAdrv/src/devices.jl:76
[6] capability(dev::CuDevice) in CUDAdrv at /home/tim/Julia/pkg/CUDAdrv/src/devices.jl:129
[7] name(dev::CuDevice) in CUDAdrv at /home/tim/Julia/pkg/CUDAdrv/src/devices.jl:51
[8] totalmem(dev::CuDevice) in CUDAdrv at /home/tim/Julia/pkg/CUDAdrv/src/devices.jl:64
[9] warpsize(dev::CuDevice) in CUDAdrv at /home/tim/Julia/pkg/CUDAdrv/src/devices.jl:121