[krisoft]

> Isn't it self-explanatory

No.

> what problem did you have understanding it?

It is simply not a phrase I commonly read. When I google it I find a visa consultancy under the name, and not much else. Curiously your comment is also among the results.

The problem is that the phrase "<something> developer" is used to describe what the person develops. A "real-estate developer" invests in real estate as a business. A "web developer" develops web applications, a "game developer" develops games, and so on and so on. So reading the word I immediately thought they mean someone who is developing the future? Like idk Douglas Engelbart or Tim Berners-Lee or someone like that.

If you want to write that someone is learning to become a developer I would recommend the much less confusing "developer in training" phrase, or even better if you just write "they are learning to become a developer".

[willsoon]

Bad English case. It just is. I pay a lot of attention when I write English, but you can always tell when someone isn't a native English speaker in about two words. Je suis désolé.

[krisoft]

No worries! Glad that trallnag asked so we could clear it up.

Wishing your wife the best of luck with her career! (and to you too!)