I bought it at Kobobooks, where you don't actually get a download option. Instead I had to install their own reader on my phone, which downloaded the book as a series of html pages, then use Sigil to create a proper ebook out of it...
If you install Kobo's free desktop app, you can download Kobo purchases to that, and they will be stored locally as unencrypted epubs. On my Mac they're found in "~/Library/Application Support/Kobo/Kobo Desktop Edition/kepub", I don't know where the Windows version puts them but it shouldn't be hard to find. The files have opaque names but you just need to add .epub to the end to make them readable.
no subject
no subject