The dotnet build command builds the project and its dependencies into a set of binaries. The binaries include the project's code in Intermediate Language (IL) files with a .dll extension. Depending on the project type and settings, other files may be included, such as:
  1. An executable that can be used to run the application, if the project type is an executable targeting .NET Core 3.0 or later.
  2. Symbol files used for debugging, with a .pdb extension.
  3. A .deps.json file, which lists the dependencies of the application or library.
  4. A .runtimeconfig.json file, which specifies the shared runtime and its version for an application.
  5. Other libraries that the project depends on (via project references or NuGet package references).
(see also: Microsoft Documentation)