Web interface uses deprecated third-party API to generate QR code
When clicking on the link to the mobile version of the web interface, a QR code linking to it is generated, that a mobile device can scan to open the mobile interface. This QR code is generated using the Google Image Charts API. There are several problems with this, including privacy implications.
First, the Google Image Charts API has been deprecated since 2012: https://developers.google.com/chart/image
Deprecation notice: While the dynamic and interactive Google Charts are actively maintained, we officially deprecated the static Google Image Charts way back in 2012. This gives us the right to turn it off without notice, which may happen soon.
Warning: This API is deprecated in 2012 and was turned off on March 18, 2019. Please use the actively maintained Google Charts API instead.
https://groups.google.com/forum/#!topic/google-chart-api/rZtHTyYgyXI
Actually, the API did go offline, but was brought back after just a couple days of downtime, with the maintainer stating:
The API was turned back on temporarily and may be shut off again without notice.
If we want to keep this feature, one option would be to at least migrate to one of the alternative, non-deprecated APIs probably mentioned in the thread linked, before this API shuts down.
However, using a third-party web API doesn't work in situations such as a LAN with no or limited internet access, and in this case, leaks the URL of the web interface over the internet as it is literally given away as input parameter in the query string. This is done without warning the user, and might not be something that they want to happen.
So a more ambitious solution to keep this feature would be to ship and use a local implementation.
Of course, a third possibility would be to simply remove the feature.