If you don't have a license from the copyright holder, you can't legally use it, except for fair use exemptions: perhaps you could write a blog post criticizing it.
> If you don't have a license from the copyright holder, you can't legally use it, except for fair use exemptions: perhaps you could write a blog post criticizing it.
To be clear, do the files contains a copyright or licence, if they do not and many companies don’t attach a copyright header to their files. Why would the assumption be that the files are not public domain or free for use
Theres nuance though, that copypasting a previous comment doesn't answer.
What about public domain works for example?
Or you had a good faith belief you had permission from the copyright holder, eg someone misrepresented themselves as the copyright holder, or the copyright holder published the code in public without a copyright notice?
Public domain: any software made to run on current machines is too new to have expired copyright; the author(s) may have dedicated it to the PD, but you have to find that dedication, which is equivalent to a license.
Good faith: that may affect the amount of damages the copyright holder can extract, but it's still illegal to use the software.
Copyright notices: haven't been required for 30 years.
Copyright older than 30 years still requires the notice (and this is banking software).
My underlying point though was that it was an unreasonable answer, to just copy paste the previous answer. No one here that I've seen has claimed to be a lawyer, and no one I've seen has defined what nations laws we are talking about. At that level of discourse, the question posed, deserved a reasonable answer.
We're talking about code. Which is more like a recipe than a novel.
If Coca Cola writes down its proprietary recipe on their entrance "by mistake", I can definitely make use of it. Maybe I can't photocopy it for sale, but I can definitely re-use their previously-secret techniques.
I can even say I got it from them through their own error and have the exact same outputs for the exact same inputs.
Trade secrets aren't your secret anymore once you publish them.
All we know in this case is that copyright law was used as a tool to remove it.
If you reverse engineer a system and write a spec using clean-room technique, it's going to be massively easier for the team to do it if they have lawful access to the no-longer proprietary source code.
And wouldn't that be the method to re-create your own copyrightable implementation of GPL code too?
As someone above posted the wider "List of parties to international copyright agreements", this is one of the boxes that need to be ticked prior to signing any form of deal between countries. It's a kind of 'fundamental' in order to start doing business with that country (or for the country to be taken seriously).
DPRK only recognises foreign copyrights, and have no concept of IP for its own works (because everything is done to superior order, there is no creativity allowed). Micronesia does not have copyright, but has even stricter regime of creative works, amounting to a patent-like protection.
If you don't have a license from the copyright holder, you can't legally use it, except for fair use exemptions: perhaps you could write a blog post criticizing it.