Web Compatibility Support • uptime-kuma based websites don't work

Uptime-kuma is a "fancy self-hosted monitoring tool". Seems to be an alternative to Xymon and similar tools.

It is open source: https://github.com/louislam/uptime-kuma

There is a demo instance: https://demo.kuma.pet/start-demo

It renders a blank page and gives the following console error:

CODE:

TypeError: this.relativeTimeFormatInstance.formatToParts is not a function

Apparently this feature is supported in Firefox since Firefox 70.

Naturally, disabling JavaScript makes it tell you to re-enable JavaScript. Unfortunate.