Ubuntu 18.04 em x86 deseja carregar repositórios arm64 [duplicado]

Como desenvolvedor, posso ter quebrado algo, pois meu 18.04 tenta carregar pacotes também (?) para arm64:

$ sudo apt update
Ign:1 http://dl.google.com/linux/chrome/deb stable InRelease
Hit:2 http://packages.microsoft.com/repos/vscode stable InRelease              
Hit:3 http://ppa.launchpad.net/maarten-baert/simplescreenrecorder/ubuntu bionic InRelease
Hit:5 http://dl.google.com/linux/chrome/deb stable Release                 
Get:4 http://archive.ubuntu.com/ubuntu bionic InRelease [242 kB]
Get:6 http://archive.ubuntu.com/ubuntu bionic-updates InRelease [88,7 kB]
Get:7 http://archive.ubuntu.com/ubuntu bionic-backports InRelease [74,6 kB]
Get:8 http://archive.ubuntu.com/ubuntu bionic-security InRelease [88,7 kB]

...

Fetched 494 kB in 2s (249 kB/s)                 

Reading package lists... Done

E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.162 80]

E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic-updates/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.162 80]

E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic-backports/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.162 80]

E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic-security/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.162 80]

E: Some index files failed to download. They have been ignored, or old ones used instead.

Por que isso está acontecendo? De onde tira isso binary-arm64?

Não há *.list em meu /etc/apt/ que inclua qualquer coisa relacionada a arm.