Browsers

WorldWideWeb, later renamed to Nexus to avoid confusion about the software and the World Wide Web, was the first web browser and editor. When it was written, WorldWideWeb was the only way to view the Web.
The source code was released into the public domain in 1993. Some of the code still resides on Tim Berners-Lee's NeXTcube in the CERN museum and has not been recovered due to the computer's status as a historical artifact.

WorldWideWeb was capable of displaying basic style sheets, downloading and opening any file type supported by the NeXT system (PostScript, movies and sounds), browsing news groups, and spellchecking. At first, images were displayed in separate windows, until NeXTSTEP's Text class supported Image objects.
The browser was also a WYSIWYG editor. It allowed the simultaneous editing and linking of many pages in different windows. The functions "Mark Selection", which created an anchor, and "Link to Mark", which made the selected text an anchor linking to the last marked anchor, allowed the creation of links. Editing pages remotely was not yet possible, as the HTTP PUTmethod had not yet been implemented. Files would be edited in a local file system which was in turn served onto the Web by an HTTP server.
WorldWideWeb's navigation panel contained Next and Previous buttons that would automatically navigate to the next or previous link on the last page visited, similar to Opera's Rewind and Fast Forward buttons; i.e., if one navigated to a page from a table of links, the Previous button would cause the browser to load the previous page linked in the table. This was useful for web pages which contained lists of links. Many still do, but the user interface link-chaining was not adopted by other browser writers, and it disappeared until it was later picked up by later web browsers. An equivalent functionality is nowadays provided by connecting web pages with explicit navigation buttons repeated on each webpage among those links, or with typed links in...