I used an online tool to analyze the file format, and I have some chances about what kind of format it was then BOOM!
When I discovered this, I thought of downloading some tool to open it on my computer, but I already had a great tool to open it already pre-installed
… by editing the file in a text editor you can guess what is its original format, as it’s written in it. Otherwise you can also try to open the file in every tool you have installed in your system, that could work too. Ooops, I said too much.