High Quality Content by WIKIPEDIA articles! The Hessling Editor (THE) is one of the older open source text editor projects (started in 1990, first released in August 1992 according to its history file). For more than ten years it has been written and maintained by Mark Hessling, who along with being the original author of THE is also a maintainer of Regina, an open source REXX interpreter that has been ported to most Unix platforms.