1x2 Tunnel backfill improvements for better security of nether locations

[SavexG]

Locations can be spotted because the Highwaytools backfiller thingy leaves that behind on Y120 I suggest it so if under it there is no space to build on it will just bridge temporarly and then destroy the briding back the only thingy that is worrying is the netherrack drops, then if you would also find a solution for that your tunnel mode with backfill is probably the savest way on 2b2t to travel to a critical location via the nether

[Avanatiker]

I need to test that one