>>715246842It depends on how they wrote it, if they made the variable private or public, if they are inheriting from any specific libraries, if the code is under a specific liscence, if they are using specific interfaces etc etc etc.
It's not always about changing the value of variable a, because variable b, c, d, or e can derive their own values from a, and by changing the value of a you have now changed the values of b, c, d, and e (this is an example of bad coding but it is something that can happen).