Welcome to the ALTO XML GitHub web pages!
ALTO (Analyzed Layout and Text Object) is a XML Schema that details technical metadata for describing the layout and content of physical text resources, such as pages of a book or a newspaper. It most commonly serves as an extension schema used within the Metadata Encoding and Transmission Schema (METS) administrative metadata section. However, ALTO instances can also exist as a standalone document used independently of METS.
The official page of the ALTO standard is http://loc.gov/standards/alto. There you will find
"ALTO XML GitHub" (https://github.com/altoxml) is used as the environment for maintenance and development of the standard. On this location you will find