Help with using pale moon source code

[DarkAwsm13]

Hi Guys,

I am new here and was wondering if someone could help me out please.
We are doing a group project at university around security and we have decided to produce a piece of software that informs the user when the master password has been entered incorrectly with details such as site accessed, date time etc....

We have the software working and used a temp form as the master password to show it working, however I would now like to add it to a real web browser to test it properly.
The issue I have though is I cant find the code where i need to add my programme to it, what I am looking for is the code that represents the attempt at input itself, i.e. checking that the password is correct and if not I want to add my functionality into it to run my software.

My question is simple, does anyone know where this code would be and could you advise.

Many Thanks