It's a thesis from a university publication catalogue, and the file name might be just conforming to some kind of a guideline from their university library. "G

It's a thesis from a university publication catalogue, and the file name might be just conforming to some kind of a guideline from their university library. "Gradu" is a common shorthand for "pro gradu" which is the term used in Finland for a master's thesis. The numbers might just be some kind of an id. Many other theses from the same archive also seem to follow some kind of a similar (though not quite identical) pattern in their file names. It's not the most descriptive file name but it might not be the author's choice.