[0] https://en.wikipedia.org/wiki/Pick_operating_system#History [1] https://en.wikipedia.org/wiki/Airplane!
Supposedly an early version would bleep out Dick van Dyke and replace it with Jerk Van Gay.
The jokes about Dick Van Dyke's name are very old (but usually they use Penis Van Lesbian), so it was quite likely just a variant used by the company itself as a PR sound-bite to get people to write about them. It seems like it worked - it appeared in quite a lot of news stories and some are still online:
https://www.latimes.com/archives/la-xpm-1998-nov-25-ca-47459...
I also have doubts because I can't see their customer base ever being ok with the word "penis", regardless of whether it is a medical term. So I can't see them making that substitution in their dictionary. Although, I wouldn't be surprised if they outsourced it and only provided a list of words to substitute that was incomplete and left choosing the substitutions up to the dev.
The box, as described by vidarh, would turn "Dyke" into "Gay".
The "penis" one refers to a joke told by Mary Tyler Moore on Letterman back in 1993, https://youtu.be/vhAv8Aowb9w?t=413 .
(https://en.wikipedia.org/wiki/Dyke_(slang) says the term "was used as a derogatory term for lesbians by straight people" by the 1950s, and is in a 1942 slang dictionary at https://archive.org/details/bwb_T5-BCF-927/page/374/mode/2up... . Since he was born in 1925, it seems possible that he encountered that term before he turned 18 in 1943.)