I contracted (writing C++) for a large international security company, and they had a ton of problems that had clearly been festering for years, maybe decades.

I contracted (writing C++) for a large international security company, and they had a ton of problems that had clearly been festering for years, maybe decades. I mostly said nothing since it seemed no one was interested. During the contract, I wrote a doc about the shortcomings, problems, and potential solutions, adding to it whenever I ran into something. From code to management to tools used. When my contract ended, I sent the doc to a couple of people who I felt needed to read it. They loved it, and passed it around to practically everyone. I had emails from offices all over the world with questions about it. I didn't renew the contract since I had already moved on to other things. If I had that time again, I would speak up, but I would do so with a well-thought-out document.