AdditionalFileValidExtensions lists any file extension the builder considers as valid.

DefaultIndexURL is the default index url.

HeaderFilesValidExtensions lists valid extensions for header files.

LibrariesIndexResource is the IndexResource to get the libraries index.

LibrariesIndexURL is the URL where to get the libraries index.

MainFileValidExtension is the extension that must be used for files in new sketches.

MainFileValidExtensions lists valid extensions for a sketch file.

SourceFilesValidExtensions lists valid extensions for source files (no headers).