This would actually work on any kind of file type I suppose...
Each time I add a .hbm.xml NHibernate mapping file to a project it is easy to forget to select "Embedded" under build action. Since I don't directly create my mappings but rather have NAnt hydrate them during my builds I wanted to automate the declaration to embed them automatically.
On a whim, I went into the .csproj file and deleted all the referenced to any .hbm.xml files and then replaced them with this :
<ItemGroup>
<EmbeddedResource Include="NHibernateMappings\*.hbm.xml" />
</ItemGroup>
Now, each time my NAnt script runs and squirts the mappings into my project folder they are automatically embedded and it's one less thing to remember upon running within VS during debugging.
Not sure this is legitimate but I haven't had any problems.