Kristian Klausen authored May 15, 2021 and Jelle van der Waa committed May 16, 2021

--output-delimiter="" apparently means use the NUL character[1].

[1] https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=0e46753d7c9519d7378cd3a4e0951a36ac32ffe7