Taking a quick look at the source code, it seems like they use map libre for displaying the map which is open source. The only thing not open source are the JawgMaps servers, which serve the tiles for the map in the app. This means that there are no closed source libraries running in the app/on your phone, the only thing happening is the app sending HTTP requests to JawgMaps to load tiles.

https://f-droid.org/packages/de.blau.android/

And an AbstractExtensibleMarkupLanguageHypertextTransformerProtocolRequestFactorySingletonBuilder!

Edge has been chromium-based for a few years now

their GitHub only contains libraries for using the DeepL API. Everything else is closed source.

I try to use middle click for definition in vscode so often because you can do that in jetbrains IDEs…