Enroute Flight Navigation is a simple, limited features but
absolutely free flight navigation app for Android, published under the GNU General Public License.
("absolutely free" also means that you have not to compare it with Skydemon or other paid software. If you want the skydemon features, please buy skydemon
)
It takes my attention because it is claimed to work with Traffic Receivers, so I tested it with my Pilotaware Rosetta, and it works, indeed!
The map shows positional traffics nearby. Their color changes from green to yellow when the traffics become near (I suppose the color turns red if they become REALLY near), they are shown as an arrow with a label with level difference and trend (increasing, standing, decreasing)
You can find more in the FAQ section on
https://akaflieg-freiburg.github.io/enroute/