Package: syncthing Version: 1.19.2~ds1-1+b4 Syncthing makes use of xdg-open to launch the web interface, therefore xdg-utils (package which contains xdg-open) should be added at least as a recommended dependency.
Output when launching syncthing-ui.desktop or: $ /usr/bin/syncthing -browser-only WARNING: Failed to open web UI: exec: "xdg-open": executable file not found in $PATH