Is it Free/open source software and does it work off-line (on lan with sometimes intermittent Internet connection and/or can clients commit while offline, eg on a train journey with many tunnels[1], or on an airplane)?
[1] "The construction was exceptionally challenging, at high altitudes in a region without roads and with a climate that saw many meters of snow in the winter and temperatures far below freezing. 113 tunnels, totaling 28 kilometres (17 mi) had to be built; the longest being the 5,311 metres (17,425 ft) Gravehalsen Tunnel, alone costing NOK 3 million and the longest tunnel north of the Alps. It took six years to build, and had to be excavated manually through solid gneiss."
[1] "The construction was exceptionally challenging, at high altitudes in a region without roads and with a climate that saw many meters of snow in the winter and temperatures far below freezing. 113 tunnels, totaling 28 kilometres (17 mi) had to be built; the longest being the 5,311 metres (17,425 ft) Gravehalsen Tunnel, alone costing NOK 3 million and the longest tunnel north of the Alps. It took six years to build, and had to be excavated manually through solid gneiss."
https://en.m.wikipedia.org/wiki/Bergen_Line