Programmers is all about answering conceptual questions about software development. Questions about implementation are off-topic here: while implementation may play a role in a question or an answer, they cannot be solely about implementation.
Asking "in what language was this product implemented" falls squarely into the off-topic category of implementation. (Note: it may be about implementation, but it is also off-topic at Stack Overflow)
Furthermore, a question should elicit reasonably long answers that describe various aspects of a topic and go in-depth. Depending on the project, I might able to answer "in what language is X implemented?" with "C++" or "Perl" or some other one-word answer. That is fundamentally not a good question or answer because there is nothing to describe.
Finally, from How do I ask a good question?
Make it relevant to others
We like to help as many people at a time as we can. Make it clear how
your question is relevant to more people than just you, and more of us
will be interested in your question and willing to look into it.
A good question will generalize a problem just enough so it is still useful to the asker, but other people can stumble on the question from Google or searching on-site and get value from it. This is one of the points of asking a question using a Short, Self Contained, Correct (Compilable), Example (or the conceptual/design equivalent to be on-topic here). Distill your question down to its core so it can be useful to others, among other benefits.
Asking a question such as the one you posited is not really interesting to most people and it will not be relevant to others. Additionally, as you found out in the comments, you are more likely to get an answer from someone involved in the project anyway.
Why are you asking this question?
Questions like the one you brought up are normally a means to an end. You see some cool feature and are curious how to implement it yourself, or how to design your software to do something similar. While most popular programming languages are somewhat equivalent from a computer science theory perspective (i.e. Turing-complete), the reality is each has its own ecosystem of libraries and language features that might make certain software easier to implement. Asking what language to use sounds like a decent first step.
You would be better off asking yourself what is my end goal? Why do I care what language was used? That should lead you to another question which may be on-topic here. Now you start getting into design questions which are interesting, are relevant to other people, and do attract high-quality answers. Of course, one must ask a good question that is not too broad (a very real risk with design questions), but now we are getting somewhere productive.