What do you put in a PIB?

Could you please elaborate on what exactly goes into a PIB, or a Program Investment Budget? I understand it's a financial planning tool used to allocate funds towards specific programs or initiatives, but I'm curious about the specific details that make up its structure. Are there any standard components that every PIB must include? For instance, do they typically outline the projected costs and revenue streams associated with the program, as well as the expected outcomes and metrics for measuring success? I'm particularly interested in how a PIB differs from other budgeting frameworks and why it's considered an effective approach for managing investments in large-scale projects or initiatives.