The Expert Handlers SIG of the Open Accessibility (A11y) Workgroup at The Linux Foundation, is exploring a standardized plug-in mechanism to Assistive Technology (AT) software. The goal of this plug-in standard is to allow AT software to take advantage of expert software that understands specialized markup. This plug-in standard will allow the expert software to provide enhanced, semantically rich access to specialized markup, so that the AT can properly render the markup visually, aurally, and/or tactilely. The plug-in would also assist users in navigating the semantic meaning encoded in the specialized markup.
To provide some background as to what needs to be supported by an expert handler interface standard, the Expert Handlers SIG has drafted the Unified Use Cases for Expert Handlers, version 1.0, which discusses a number of use cases for an expert handler. The uses cases are divided into various functionalities such as speech output, alternative input, navigation, and braille generation. The last section discusses the options for how an expert handler might fit into the sequence of events that eventually results in a response to a user action.