n. (also eXtensible Markup Language, abbr. XML)a standard for encoding structured documents and creating schemas to validate such documentsPitti 1997, 278In 1996 the World Wide Web Consortium (W3C) founded the XML Working Group to build a set of specifications that would make it easier to use SGML on the Web. The working group, in a short period of time, wrote a specification for a simplified subset of SGML named Extensible Markup Language (XML). . . . ¶ The motive behind the development of XML is the recognition that HTML will not support complex, community-based use of shared information on the Internet.McKemmish et al. 1999, 30It is anticipated that future use of metamodelling will lead to the development of a RDF schema, enabling the expression of the RKMS in Extensible Markup Language (XML). XML is a method for designing and putting structured data in a text file. It has a number of features that are useful in archival descriptions: it is unambiguous, easy to generate and read (by a computer), extensible, supports internationalization, and is platform-independent. Additionally, XML files can be self-describing—that is, they can contain a definition of their own structure.Doylen 2001, 3XML documents are containers for information. Within the primary container may be information and more containers, which themselves may contain information and more containers. These named containers form neatly hierarchical structures, creating an incredibly flexible and remarkably powerful framework for storing and exchanging information of all kinds, from memos to database tables to poetry to program structures to invoices. XML documents may also include or reference sets of rules describing their structures, which applications may use to validate that documents conform to those rules.Rubinstein 2017, 303Aside from HTML, SGML was never widely adopted . . . To address this issue, the World Wide Web Consortium (W3C), an organization that supports the management and creation of Web standards, developed the eXtensible Markup Language (XML), which became a W3C recommendation in 1998. XML is a much simpler standard, relying on just five basic rules for creating a well-formed XML document and, eventually, a suite of standards for creating more complex, domain-specific rules known as schemas, for validating instances of XML documents.Velte 2018, 114Unlike Web archiving more generally, collecting social media as data sets usually involves using the social media platform’s application programming interface (API) to harvest content and associated metadata in formats like JSON or XML.Wiedeman 2019a, 399In practice, EAD was inevitably tied to the medium of XML, as archivists would store data as encoded text.Wiedeman 2019a, 407XML was never widely used over relational databases for permanent and authoritative information stores governed by schemas and namespaces as most of library and information science literature envisions. While XML found general use for configuration files and derivative formats for data read by web pages, the rise of Web Application Frameworks, REST APIs, JavaScript everywhere, and JSON has further marginalized XML. As the architecture of the Web became more complicated, XML proved to be complex, verbose, and variable, and many technologists relied on web applications, backed by data models and accessed by REST APIs, as more effective and maintainable solutions for storing and transferring data.
