I assume you see that "their programmer's editor" is obviously wrong, so I'll skip it.
Finding a product named Programmer's Editor doesn't support the claim that "programmer's editor" is natural, normal, idiomatic English (and the author of the program by that name, in addition to being weirdly incapable of even correctly defining "programmer," isn't clearly a native speaker). Quite the contrary. You wouldn't name a program Code Editor, IDE, Editor, or Text Editor, just as you wouldn't name a company or a line of products Computers, because these are too generic to be used as proper nouns.
And the ngram of "programmer's editor" speaks for itself: https://books.google.com/ngrams/graph?content=programmer%27s...
To the best of my knowledge, at no time in the history of English has "programmer's editor" been idiomatic English, either inside or outside of the world of software and engineering. And today, in late 2024, it is unarguably incorrect usage, regardless of its history.