What is a user agent?

Here's a version of the email that I sent to Jeanne during Monday's call. This is not about different levels of conformance, but rather the high-level question of what UAAG applies to and what it doesn't. This was an input going into Jeanne's later email to the group. Any things that don't fit into these categories?


      What is a user agent?

Things to which UAAG would apply:

  * User agents:
      o *Stand-alone web browsers*, including shells around user agent (e.g. Chrome, Firefox, IE, Safari)
      o *Embedded web browsers* that provide user agent features in applications that would not otherwise be a user agent (e.g. the Web Tools Platform which provides web language editing within the Eclipse integrated development environment)
      o *Editors that render web technologies* even though that may not be their primary purpose (e.g. Microsoft Word)
      o *Authoring tools* that use and render web technologies (e.g. Microsoft FrontPage, MacroMedia DreamWeaver)
      o *Web-based user agents* (e.g. ...?)
      o *Media Player applications *that render a limited set of web technologies (e.g. Windows Media Player, RealPlayer)(may be stand-alone or also be plug-ins)
      o *Application that renders a constrained set of web data* (e.g. American Airlines app for smartphones that downloads and renders a constrained set of XML data from a dedicated server)
  * Extension of Plug-In:
      o *User agent extensions that changes content* (e.g. Mouseless browsing add-on for Firefox, which inserts alters the content stream)
      o *User agent extensions that alters user agent UI* (e.g. HeadingsMap which adds another navigation pane, IE Tab which adds a tab whose contents are rendered using Trident instead of Gecko, Copy Plain Text which adds a command to the context menu)
      o *User agent plug-ins that handle content types* (e.g. Flash Player, AlternatTIFF ActiveX control, Bento skin that adds a Trident-based browser window to Winamp)
  * Platforms:
      o *Web Toolkits designed for specifically user agents* (e.g. Gecko, KHTML, Presto, Trident, WebKit, Perl modules for parsing HTML)

Things to which UAAG20 would not apply:

  * *Basic text editors* that do not process or distinguish between web technologies (e.g. Notepad)
  * *Operating environments* that include web toolkits and/or stand-along user agents (e.g. Windows, OS X, KDE, iOS)

  * *General-purpose platforms or toolkit *that don't use**web technologies, even though they may be used by user agents for other purposes (e.g. Gnome, KDE, .NET Framework/CLR, iOS?)
  * *Non-Web extensions or plug-ins* where the host is not a user agent, but can also be hosting user agents, as long as the extension or plug-in does not itself use web technologies and is not designed specifically to work with other extensions or plug-ins that do (e.g. a general-purpose add-in for the Eclipse integrated development environment, even though it may be used with and interact with the Web Tools Platform extension which adds user agent capabilities to Eclipse).

Not sure about these:

  * *Text editor with syntax checking and highlighting* as they do specifically process web technologies, but do not use the rules for rendering them in the sense that user agents do (although of course they do render them in another way) (e.g. Notepad++, TextWrangler, VIM)
  * *General-purpose add-ins* for general-purpose applications that are also user agents (e.g. would all add-ins and macros for Microsoft Word be user agent extensions because Word is a user agent, even though the author is not even aware of that fact?)