GuidoViewer 1.1 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. GuidoViewer for Mac belongs to Audio & Video Tools. This free Mac application was originally designed by GRAME.
From the developer:
GuidoViewer is designed to render Guido Music Notation (GMN) files with automatic music formatting. It supports Quartz, multiple pages, multiple documents, zoom, and printing.
The GMN format is a formal language for score level music representation. It is a plain-text, human-readable and platform independent format capable of representing all information contained in conventional musical scores.