Ubuntu installation instructions fail when apt update

[ArneBachmann]

Describe the bug
I followed the instructions on https://celestiaproject.space/ubnt.html and got this error:

ash@Mini:~/Desktop$ sudo apt update && sudo apt install celestia
E: Missgestalteter Eintrag 1 in list Datei /etc/apt/sources.list.d/celestia.list (Component)
E: Die Liste der Quellen konnte nicht gelesen werden.

(mal-formed entry in line 1):

ash@Mini:~/Desktop$ cat /etc/apt/sources.list.d/celestia.list 
deb https://celestiaproject.space/ubuntu/ main
deb-src https://celestiaproject.space/ubuntu/ main

Mh I guess version 23 is not supported... My bad.

PRETTY_NAME="Ubuntu 23.10"
NAME="Ubuntu"
VERSION_ID="23.10"
VERSION="23.10 (Mantic Minotaur)"
VERSION_CODENAME=mantic
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=mantic
LOGO=ubuntu-logo

[375gnu]

We support only LTS versions. You can build from sources.

[ArneBachmann]

Makes sense. Thanks!