An extension to add sources is available, but the site works fine without it, requires excessive permissions that could be unsafe, and it isn't auto-dated, so we'd recommend either avoiding it, running it only on a separate browser profile, or ideally a completely fresh browser you have no personal data on.

Remember to click the extension icon and enable it on the instance you're using otherwise it wont work. The main host (NSBX) may break when the extension is enabled.

https://docs.undi.rest/extension