The two tasks T4292 (Rewrite vyatta-save-config.pl to Python) and T4295 (Use config_tree instead of legacy loadFile in vyos-load-config.py) go together in the sense of removing legacy code; they have a common dependency T4291 (Consolidate component version read/write functions).
They are gathered here to present one PR; all complete, but for a trivial bug and testing.