They are interested not in specific libraries (they readily googling, and even if they want to, then it’s not difficult to write one myself, although if you recommend something interesting or popular, it’s a separate plus sign), but the approach as a whole.
Where to carry out localization? on the front or on the server? I can use Java + Spring with already built-in localization support, but it turns out that it’s not nice, the server turns out to be interfering with the frontend. On the other hand, if you generate everything using js, search engines may not pick it up, you need to execute js code (although it may not be necessary, usually only the interface is translated).
In general, I have thoughts on this matter, but it can all be decided long ago, and I just have to bicycles here)