Visual Build projects are stored in files with a .bld or .bldx extension.

 

When saved with a .bld extension, the project file is stored in XML format with UTF-8 encoding (including a BOM [byte order mark] if the related option is enabled), which can be stored as text in a source control system.

 

When saved with a .bldx extension, the project file is stored in a compressed format and encrypted with 256-bit AES encryption.  When specifying an edit password, it is more secure to save the file compressed and encrypted with a .bldx extension to prevent the edit password from being removed from the .bld file.  When specifying a project password, the project password is also used as the key for encrypting the .bldx file (otherwise a hard-coded encryption key is used), providing additional security for the content of the project file.