Not full knowledge. But you should know about every single dependency, know what they do and if they're from a trustworthy source. Being able to say with confidence that you aren't installing malware on your customers machines is the least you can do.

On the developer side there's more though, you should know what their release cycles are like, how they manage compatibility, how long they support older releases etc. You don't what your app stuck in a 3 month upgrade cycle just because a transitive dependency needed an update.

There's a reason dependencies are there own form of technical debt and need to be minimized.