In my opinion the biggest problem with legacy code is understanding its implementation as someone who hasn&#x27;t worked on it before. In a lot of cases it&#x27;s not documented well and the original authors have already left, so there&#x27;s no one to ask. You are left with reading code written by someone else, which takes a lot of time.<p>This is not Perl related, but I&#x27;m currently working on a developer tool that makes this part of the job easier. It&#x27;s a source explorer for C&#x2F;C++ named Coati that simplifies navigation within source code and thereby makes understanding the implementation faster and easier. <a href="https:&#x2F;&#x2F;www.coati.io&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.coati.io&#x2F;</a>