All right, this is all I needed to know cited from that page:<p>&quot;XBase [...] is a general term for languages and tools derived from the Ashton Tate dBASE product, popular in the 1980s and early 1990s. Clones include FoxPro, Quicksilver, dbXL, and a compiled dialect called Clipper (which spawned XbasePlusPlus, FlagShip, and Harbour).&quot;<p>&quot;XBase originated as a table-oriented non-SQL language and tool vaguely influenced by relational theory and (mainly) cursor-oriented table navigation techniques from the 1960s. It was one of the first products that easily allowed small businesses access to database concepts such as ad-hoc queries, indexing, and data-driven CrudScreen RAD when microcomputers were just coming of age. [...]&quot;<p>&quot;It allegedly has its roots in a legacy database product called RETRIEVE. The Pasadena Jet Propulsion Laboratory, famous for planetary probes, didn&#x27;t want to pay licensing fees for RETRIEVE and so set out to create something similar. In a round-about way, it eventually wound up a commercial product for CPM microcomputers, and grew quite popular in the DOS world.&quot;<p>There is an open source implementation at <a href="http:&#x2F;&#x2F;harbour-project.org&#x2F;" rel="nofollow">http:&#x2F;&#x2F;harbour-project.org&#x2F;</a> (-&gt; <a href="http:&#x2F;&#x2F;harbour.github.io&#x2F;" rel="nofollow">http:&#x2F;&#x2F;harbour.github.io&#x2F;</a> ) whose latest version 3.0.0 was released on 2011-07-17, but the Github repo (imported from SourceForge) shows recent activity: <a href="https:&#x2F;&#x2F;github.com&#x2F;harbour&#x2F;core" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;harbour&#x2F;core</a>