File-Extensions.org might be a bit more popular than Microsoft Visual Studio. We know about 1 link to it since March 2021 and only 1 link to Microsoft Visual Studio. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
While the editor seems to old fashioned there isn't anything particularly wrong in using it for learning. Alternatively you can propose to your teacher about https://visualstudio.microsoft.com/vs/express/ . IMO editor is not a big factor when we are talking about high school learning. Source: about 3 years ago
File-extensions.org lists following files for .3 extension:. Source: about 1 year ago
IntelliJ IDEA - Capable and Ergonomic IDE for JVM
FileProInfo - It's All About Files, Software, Online Tools - 100% Free
Xcode - Xcode is Apple’s powerful integrated development environment for creating great apps for Mac, iPhone, and iPad. Xcode 4 includes the Xcode IDE, instruments, iOS Simulator, and the latest Mac OS X and iOS SDKs.
FileInfo.com - FileInfo is the central file extensions registry and contains a database of over 10,000 file types.
Visual Studio Code - Build and debug modern web and cloud applications, by Microsoft
FILExt - Open, view and convert files online