Writing from my experience as a software developer.
First, to sort out the most important thing.
That original author holds copyright over that work and to do anything with it you must obtain a license. Under
Berne Convention, which is the foundation of copyright laws across the planet, obtaining copyright is automatic and requires no registration or other formalities. As soon as they created the code, they became the exclusive owner of their work and anyone must get a permission to do anything, unless covered by some exceptions in your local law.
(1) So no: you can not simply fork it, as suggested above, or depend on whether they put a notice in the sources. The source being available is irrelevant here. You can’t take it, just like you can’t snatch a bag someone left in their car with the window open.
Which basically closes this case, if you can’t contact the author. That kinda falls under the concept of
orphaned works, but recognizing a work as orphaned and using that in your defense are two different beasts. The latter is stepping on extremely thin ice even for old works. Using it for something that clearly has a living and still active owner is borderline suicidal, unless your local law makes very explicit exception there. If you suspect it does, consult a lawyer, not random people on a forum.
You may still try to determine the author by finding connections they might’ve had with other projects. You may also see if you can’t find the code elsewhere. Though tiny, there are chances they themselves copied it from someone else. Or that it is being developed by another party, which itself is big enough to take the hit and shield you
(2) in case the original author wakes up.
On less practical and more philosophical part: that’s an unfortunate fallout of ideas being understood only superficially and hostility towards red tape. In the case of people who oppose copyright: not understanding, that the law still applies to them. That’s a story repeated over and over again, with people not being explicit about licensing terms and thinking it’s equivalent to putting your work in the public domain.
(3) Not only it’s not, it makes the entire situation even worse.
(1) For example US
fair use and counterparts elsewhere,
de minimis rule,
nationalization, emergency, specific exceptions for science, education and religion, and so on. Neither of which applies to your case, I suppose. Either because it simply does not, or because it’s not used for software in practice (
de minimis).
(2) A random student, that forked it for their course project is not such an entity. More towards stable companies of reasonable size.
(3) Which, in many many places, can’t even legally be done. Hence Creative Commons 0.