Hello! I don't know if this project is still maintained, but I tried to run it on a MacBook Air with macOS 10.15.5, and I got this exception. I downloaded the x86_64 macOS binary.

2020-07-21 00:08:36.005 tclkit[4386:384806] -[TKWindow setCanCycle:]: unrecognized selector sent to instance 0x1005782a0
2020-07-21 00:08:36.008 tclkit[4386:384806] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[TKWindow setCanCycle:]: unrecognized selector sent to instance 0x1005782a0'
*** First throw call stack:
(
	0   CoreFoundation                      0x00007fff32e41be7 __exceptionPreprocess + 250
	1   libobjc.A.dylib                     0x00007fff6bc195bf objc_exception_throw + 48
	2   CoreFoundation                      0x00007fff32ec0c77 -[NSObject(NSObject) __retain_OA] + 0
	3   CoreFoundation                      0x00007fff32da644b ___forwarding___ + 1427
	4   CoreFoundation                      0x00007fff32da5e28 _CF_forwarding_prep_0 + 120
	5   tclgqgUaY                           0x000000010354c786 ApplyWindowAttributeFlagChanges + 1265
	6   tclgqgUaY                           0x000000010354cb7f TkMacOSXApplyWindowAttributes + 51
	7   tclgqgUaY                           0x000000010354c0e9 TkMacOSXMakeRealWindowExist + 1269
	8   tclgqgUaY                           0x000000010354e4d4 TkWmMapWindow + 58
	9   tclgqgUaY                           0x00000001034b3b12 Tk_MapWindow + 84
	10  tclgqgUaY                           0x00000001034be8ba MapFrame + 62
	11  tclkit                              0x00000001000c460b _ZNK10c4_ColIter6BufLenEv + 586465
	12  tclkit                              0x00000001000a9526 _ZNK10c4_ColIter6BufLenEv + 475644
	13  tclgqgUaY                           0x000000010349b8cf Tk_MainLoop + 29
	14  tclkit                              0x00000001000a272a _ZNK10c4_ColIter6BufLenEv + 447488
	15  tclkit                              0x000000010000121a tclkit + 4634
	16  tclkit                              0x0000000100000d34 tclkit + 3380
	17  ???                                 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException