[anders_p]

It's not that simple.

When developing software, a company might aquire a license to add some library or code to their product.

This happens all the time with OS's like Windows (licensing the ability to play media formats, etc.) or games (licensing certain engines or algorithms).

That doesn't mean the company squired a license to release the libraries or code as open source 20 years later.

So you'd have to go through the codebase with a fine-toothed comb, line-by-line, because the original developers don't work for you anymore, and the license agreements are long lost.

Releasing large software projects are a massive cost to any company that wants to be protected from potential lawsuits.