The way to debug depends on what kind of protection a game is using, but generally I don't bother cracking the encryption.
In this case, if you check what is being tested you'd find
if _testcode == setup.decrypt($mcCache), and then you'd see that the variable is set to
(State.variables.mcCache = 'tpncsb';.
Then you can use the decrypt function itself to get the value:
View attachment 4052041
That said, when breaking an access code in a game, always look for the weakest point, which will usually be a boolean (true/false) statement.
For example, in this case you could simply replace
if _testcode == setup.decrypt($mcCache) for
if true, which would make any code work.
You could also overwrite the decrypt function from the console like
SugarCube.setup.decrypt=function(){return 'a';}, which would set the correct passcode to the letter a.
There's usually a dozen ways to break each game. Always go with whatever is easiest/more comfortable to you.
