What I hate about .NET is the atrocious naming.
Net Core, Net Framework, Net Common Core, .NET..
And God forbid any of these frameworks ever expose what they are in a config file. You start a project, hand it to a colleague and he can't figure out whether it's Framework or Core by looking at the files. You Google and are immediately bombarded by 15 year old threads.
If you start a project with .NET Framework in 2026, you're doing it wrong, plain and simple.
And the .csproj files do tell you which .NET they are.
<TargetFrameworkVersion>v4.</TargetFrameworkVersion> or <TargetFramework>net4</TargetFramework> is the old framework. Also, if the file is an unreadable mess listing all .cs files, it's generally .NET Framework.
<TargetFramework>netstandard2.0</TargetFramework> is .NET Standard 2.0, which means this library can be consumed from either Framework or modern .NET.
And finally, <TargetFramework>netX.0</TargetFramework> (X >= 5) is the modern .NET.
Most web projects use JSON files for configuration. There are also some XML files for project configuration. If anything, you can run into too much configuration files.