I used to do that a year or two ago and it was pretty straightforward back than (there was Export to epub link or something like this on the left pane of a Wikipedia page). Not any more! Currently, there are two options for export in the book creator, namely, pdf and plain text (only pdf for single article).
What is worse I did not manage to find any clear info on why it is not there. The article at https://en.wikipedia.org/wiki/Wikipedia:Tools#PDF.2C_EPub.2C_Odt_and_LaTeX mentions it is still possible to produce epubs and re-directs to some weird page.
Do I miss anything obvious or they really disabled this useful functionality for good?
By the word «weird» I meant the application (or at least its web version) is half-baked. It regularly gives me «Not enough resources availiable to process your request! Your request has been dropped!». When it does work, the process takes a couple of minutes (even for small pages). There is no version for Windows, the author offers to set up a virtual machine with Linux instead. Virtual machine just to export a page to epub!? I beleive it to be an outright overkill.
– S. N. Aug 26 '17 at 15:00