This userscript from 2016 still works:
Install a userscripts add-on for your browser (Firefox, Chrome), e.g. Greasemonkey, Tampermonkey, Greasefork etc.
Then install above mentioned script, visit your Amazon wishlist and click newly added "Export wishlist" button to receive your ...
Here's a new script, on the basis of @mrts answer, but which allows to only export one list with a specific Title.
For convenience, it also exports card labels.
Found it useful to export resolved issues after update :
const board_name = "Client update - 1.0.0"
var s = ;