MSBuild response files
Response (.rsp) files are text files that contain MSBuild.exe command-line switches. Each switch can be on a separate line or all switches can be on one line. Comment lines are prefaced with a # symbol. The @ switch is used to pass another response file to MSBuild.exe.
MSBuild.rsp
The autoresponse file is a special .rsp file that MSBuild.exe automatically uses when building a project. This file, MSBuild.rsp, must be in the same directory as MSBuild.exe, otherwise it isn't found. You can edit this file to specify default command-line switches to MSBuild.exe. For example, if you use the same logger every time you build a project, you can add the -logger switch to MSBuild.rsp, and MSBuild.exe uses the logger every time a project is built.
Directory.Build.rsp
In version 15.6 and later, MSBuild searches parent directories of the project for a file named Directory.Build.rsp. This file can be helpful in a source code repository to provide default arguments during command-line builds. It can also be used to specify the command-line arguments of hosted builds.
You can use the syntax %MSBuildThisFileDirectory% in a Directory.Build.rsp file, to refer to the directory that contains the Directory.Build.rsp file. This syntax requires percent signs on all operating systems, like Environment.ExpandEnvironmentVariables, even though MSBuildThisFileDirectory isn't an environment variable.
Disabling response files
To disable automatically processing the default response files MSBuild.rsp and Directory.Build.rsp in a particular invocation of MSBuild, use the command-line option -noAutoResponse. Any response files referenced explicitly using the @-syntax on the command-line are still processed. See MSBuild command line reference.