Original author of project that a company abandoned I'm the original author of a project that was made on company time and resources. While waiting for this project to come to life it just died without any support on marketing it and not using it at all. Now I'm wondering if I can use this as my own releasing it for proprietary purposes or as an open source project. Are there legal outcomes when in the case of the company taking it back as their own proprietary product? I'm no longer an employee on said company.
Using it without permission is copyright infringement and illegal. Legally, you can try offering money to the company for the copyright or for a suitable license. For example offer them $1000 for a copy of the code licensed under the GPL license. If they accept, you are fine.
Company B has created a derived work from company A's copyright-protected work, so yes, B has infringed on A's copyright. It might be difficult for A to prove it, however, so B might get away with it, but it's still infringement. On the other hand, if B creates software that behaves like A's through reverse engineering, that is, by examining the program's function without examining its code, then they will not have infringed the copyright in the code.
Using this answer on Open Source Stack Exchange, If a repository has no license, then all rights are reserved and it is not Open Source or Free. You cannot modify or redistribute this code without explicit permission from the copyright holder. If a project doesn't have a licence, then normal copyright rules apply - this means that the author reserves all rights. The way a project is obtained, nor (except in exceptional cases), does not alter the ownership of copyright of a project. Bob will always hold copyright, unless he releases a legal document, such as a licence, that grants others various rights to the project.
They have copyright in their additional text, and possibly in things like their visual design choices (fonts, layout etc). They may also have introduced a few deliberate typos to detect any literal copies from their version (rather as mapmakers add a few imaginary features to their maps). None of this creates any rights to the original text. You are still free to produce your own copies of the original text. Just get it from some other source so you can be sure not to include anything of theirs.
No Let’s assume the most generous interpretation: you came up with a fully fleshed-out idea for a television show - name, characters, plot, scene-setting - the lot. You told this idea over the phone to someone else who made this show incorporating every single part of your idea. Here’s the rub: nobody owns ideas. Unless you had them sign a non-disclosure agreement before you told them (which you didn’t), they are free to use your ideas however they like.
When a company stops existing for whatever reason, then its assets (physical, financial, intellectual or otherwise) don't stop existing. When the company dissolves voluntarily, those assets usually go to the owner(s) of the company. When the company got bought up and integrated into another company, the buying company will usually own them. When the company went bankrupt and got liquidated, then they will often get sold off to the highest bidder. And then there is the question of who actually owns the IP rights to a specific game asset. Often there is not just one legal person which worked on a game. In addition to the developer, there might also have been a separate publisher who might or might not own IP rights. There might have been investors in the background who financed the project and now own some copyrights. Sometimes there was more than one publisher. And sub-contractors might have been involved in the development who only licensed their assets but retained copyright. So unfortunately it is often not really clear what happened to IP assets of a defunct company. People who might have the rights will often not care much about them until something happens which gives new commercial value to those assets. So even if you are unable to determine who owns the assets to a game, as soon as you start using them, someone might show up with a plausible claim to the IP rights and demand money from you. Such lawsuits can get really messy and really expensive. For a good example for just how much of a goose chase you might be in for when you want to legally obtain the rights to a game from a defunct company, check out the story of the re-release of No One Lives Forever. tl;dr: multiple game companies said "Maybe we have the rights to the game according to some contract buried in some file cabinet, but we don't care enough to find out. But if you try to release it, we will find out and if we do we will sue you!"
My understanding is that here "derived from the program" means "created by modifying the source code of the program" and not "created by running the program". Certainly that is the way all users that I have heard of treat the matter. Note that a commercial program, such as a word processor, will be fully protected by copyright, but the maker does not claim to have any rights over documents written using it. "Derived" here seems pretty clearly to mean "derivative work" in the sense in which that term is used in copyright law. In copyright law "derived work" is a term of art with a definition specific to that field.
In Germany, there is no concept that corresponds directly to public domain. You automatically hold the Urheberrecht (~ copyright) for all creative works that you make, and it can't be given up or transferred (§29 UrhG). The work only enters the Gemeinfreiheit (~public domain) 70 years after your death. You can however license Verwertungsrechte (economic usage rights). When you make creative works in the course of employment (see §43 UrhG), your employer automatically gets the Verwertungsrechte necessary in the context for the work, which is typically an exclusive right (no one else, not even you, can use the work). Your are not in an employment relationship with your school, so it has no rights to your works and cannot prevent you from publishing them on copyright grounds. When you see advice on the internet to check with your school first, that is U.S.-specific advice. Since you're still a minor (7–17), you only have limited capacity to enter contracts or legal transactions (bedingte Geschäftsfähigkeit). While you are able to make transactions involving your own means (e.g. buying something with your pocket money) or make transactions that are only to your benefit (such as accepting a gift), other transactions are schwebend unwirksam (~ pending ratification), until your parents agree. The relevant law is in §107 and §108 BGB. This is a problem with open source licenses. If you publish software under a license, this license is schwebend unwirksam. Someone might start using the software under the license. But then if your parents refuse ratification, the license would be invalid, and everyone would have to stop using your software and destroy any derivative works they made. This is a bit of a problem, especially since open source licenses are otherwise assumed to be irrevocable. So if you want to offer a license (including open source licenses), please give legal certainty to the recipients of the license and ask your parents for their consent first, possibly even in writing. Per §107 BGB, the license you offer with their consent will be valid.