mechanical-smp-v1/web/pack/config/visuality/particle_emitters/block_step.json

{
  "enabled": true,
  "interval": 10,
  "entries": [
    {
      "block": [
        "minecraft:soul_sand",
        "minecraft:soul_soil"
      ],
      "particle": {
        "type": "visuality:soul"
      }
    }
  ]
}