As their website states: “We aim to bring to light the decisions by music collectors over the decades and a digital reference collection of underrepresented artists and genres. The digitization will make this less commonly available music accessible to researchers in a format where it can be manipulated and studied without harming the physical artifacts. We have preserved the often very prominent surface noise and imperfections and included files generated by different sizes and shapes of stylus to facilitate different kinds of analysis.”
Typically made of brittle shellac, 78rpm discs were the immediate precursor to the modern vinyl LP format, and fell out of use around the 1950s.
You can join the project here, which is seeking contributors of information and metadata, and is also accepting donations of 78rpm collections.