In a .csproj file, what is for?

Question

How is

different from

?<

Answer 1

The MSDN article on the build action property explains the differences.

None - The file is not included in the project output group and is not compiled in the build process. An example is a text file that contains documentation, such as a Readme file.

Content - The file is not compiled, but is included in the Content output group. For example, this setting is the default value for an .htm or other kind of Web file.