matrix-spec/content/rooms/fragments/v1-floaty-power-levels.md

m.room.power_levels Events Accept Values as Floats

When the value is a float, anything after the decimal point is removed, making e.g. 5.17, 5.42, and 5 functionally identical.

For example, this is a valid m.room.power_levels event in this room version:

{
  "content": {
    "ban": 50,
    "events": {
      "m.room.power_levels": 100
    },
    "events_default": 0,
    "state_default": 50,
    "users": {
      "@example:example.org": 100,
      "@alice:localhost": 50,
      "@bob:localhost": 50.57
    },
    "users_default": 0
  },
  "origin_server_ts": 1432735824653,
  "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
  "sender": "@example:example.org",
  "state_key": "",
  "type": "m.room.power_levels"
}

In this example, both @bob:localhost and @alice:localhost have the same effective power level of 50, even though the values are visually different.