registryUrl vs registry2Url

Product support
1

When running balena-cli, it outputs something like:

Balena version: 17.4.9
Balena CWD: /balena
Balena settings:
---------------------------------------------
balenaUrl:            openbalena.yourdomain.com
apiUrl:               https://api.openbalena.yourdomain.com
vpnUrl:               vpn.openbalena.yourdomain.com
registryUrl:          registry.openbalena.yourdomain.com
registry2Url:         registry2.openbalena.yourdomain.com
deltaUrl:             https://delta.openbalena.yourdomain.com
dashboardUrl:         https://dashboard.openbalena.yourdomain.com
proxyUrl:             devices.openbalena.yourdomain.com
tunnelUrl:            tunnel.openbalena.yourdomain.com
dataDirectory:        .
projectsDirectory:    /home/runner/BalenaProjects
cacheDirectory:       cache
binDirectory:         bin
imageCacheTime:       604800000
tokenRefreshInterval: 3600000
apiKeyVariable:       BALENA_API_KEY
noAnalytics:          1
noSentry:             1
---------------------------------------------
Logging in to balena
 _            _
| |__   __ _ | |  ____  _ __    __ _
| '_ \ / _` || | / __ \| '_ \  / _` |
| |_) | (_) || ||  ___/| | | || (_) |
|_.__/ \__,_||_| \____/|_| |_| \__,_|

I know what registry2Url is, as all the open-balena components reference it and balenaOS reads it from config.json and pulls images from it… but what is registryUrl used for? These come from:

but I can’t seem to find anything else using registryUrl. There are some really old code items that still reference registry.balena-cloud.com, but it doesn’t resolve anymore whereas registry2.balena-cloud.com does.

is registryUrl just some vestige of the past? Should we just ignore it wherever we see it?