I want the ability to record within or alongside the code, about potential changes which can occur to that code,

An example is that I wish to signal different places where potential systems could be used. I then want to be able to aggregate all of those so that I can judge the impact of that new system.

Would markdown referencing style like: [Referenced place](Referenced%20place.md) in comments be sufficient? Well I dont think I have software that can parse this, If this format is followed then I can use a tool such as grep later