DAVx⁵ ist eine freie, quelloffene Anwendung, die das CalDav, CardDav und WebDav Protokoll sprechen kann. Das sind Protokolle um Kontakte, Kalender und andere Dinge (z.B. generische Dateien) über HTTP zu synchronisieren.

Z.B. kann man eine Nextcloud und dessen Kalender und Kontakte Funktionalität gut über dieses Protokoll verwenden.

The problem with live traffic awareness is, that it needs a lot of data to be collected all the time, something only Google or Apple with their monopolistic and privacy invasive ppwer can do. How it works (simplified) is that Google can detect if a lot of phones are on the same street and therefore assumes traffic. This data is, however, proprietary to Google. A FOSS App has the following problems:

• Too small of a userbase, to reliably track something
• Privacy conscious userbase, not wanting to be tracked
• If it had auch a feature, it would be opt-in, as FOSS does (usually) not try to be as evil as Google&Co.
• Usually limited server capacity to calculate if an aggregation is traffic

Solutions would be:

• Google is forced to make the data publicly available per API as part of some anti-monopolistic ruling
• A thrid party (e.g. cities) have their own monitoring of traffic and give public access to it.

So sadly similar dunctionality will not come in the near future in any FOSS app.