Add "mass_teleporter":{} to unit's json and ORDER_MassTeleport to unit's command_caps in json and you will see a new order in game that you can use to teleport the unit.
I was wondering what that was - but my leading theory was return teleport through helios which didn't make the cut.
It's hard to say where things start and end, but these properties might be worth poking at. phasing_duration phasing_health_frac fixup_radius energy_drain energy_cost target_types Edit: there may be other properties that use existing names; each string is only stored once.
Apparently it was being considered for a bot (support commander?) - base_bot has an fx_offsets for type: phasing. p.s. Client strings had 'unit_cap' before 'target_types', but the next section looks like it was about transports, so they might both be about that.
unit_cap is used in ai_config.json, not sure what target_types should do, it seem to only accept one instace of Unittype...