I dunno. Effectively, it's just a frontend for a TCP protocol that's used to communicate with the program being debugged: this allows for remote debugging and a

I dunno. Effectively, it's just a frontend for a TCP protocol that's used to communicate with the program being debugged: this allows for remote debugging and all manner of fun. They probably picked TCL because it's really good at GUIs, which is the brunt of the work feathers is doing, as most of the heavy lifting is done program-side, in scheme. But that's just a guess, if you really want to know, I'd ask Felix: He's the lead developer on Chicken, and he's the one who actually wrote the thing and pushed the commit (see https://code.call-cc.org/cgi-bin/gitweb.cgi?p=chicken-core.git;a=commit;h=86010b507bef896d0b744c47633eb0ede8218a4e https://code.call-cc.org/cgi-bin/gitweb.cgi?p=chicken-core.g...). He's also pretty approachable.