Clarifications on histograms format about telemetry-server HOT 4 OPEN

{
  "SEARCH_COUNTS": {
    "google.searchbar": {
      "sum_squares_hi": 0,
      "values": {
        "1": 0,
        "0": 1
      },
      "histogram_type": 4,
      "bucket_count": 3,
      "sum_squares_lo": 1,
      "range": [
        1,
        2
      ],
      "sum": 1
    }
  },
  "ABOUT_ACCOUNTS_CONTENT_SERVER_LOADED_RATE": {},
  "DEVTOOLS_WEBIDE_CONNECTED_RUNTIME_ID": {},
  "DEVTOOLS_HUD_APP_MEMORY_NAVIGATIONLOADED_V2": {},
  "ABOUT_ACCOUNTS_CONTENT_SERVER_FAILURE_TIME_MS": {},
  "DEVTOOLS_HUD_APP_STARTUP_TIME_SCANEND": {},
  "BLOCKED_ON_PLUGIN_INSTANCE_DESTROY_MS": {},
  "DEVTOOLS_HUD_APP_STARTUP_TIME_NAVIGATIONLOADED": {},
  "BLOCKED_ON_PLUGIN_MODULE_INIT_MS": {},
  "ADDON_SHIM_USAGE": {
    "[email protected]": {
      "sum_squares_hi": 0,
      "values": {
        "5": 0,
        "7": 0,
        "6": 4
      },
      "histogram_type": 1,
      "bucket_count": 16,
      "sum_squares_lo": 144,
      "range": [
        1,
        15
      ],
      "sum": 24
    },
    "{b9db16a4-6edc-47ec-a1f4-b86292ed211d}": {
      "sum_squares_hi": 0,
      "values": {
        "5": 2,
        "4": 0,
        "7": 0,
        "6": 7
      },
      "histogram_type": 1,
      "bucket_count": 16,
      "sum_squares_lo": 302,
      "range": [
        1,
        15
      ],
      "sum": 52
    },
    "{d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}": {
      "sum_squares_hi": 0,
      "values": {
        "9": 1,
        "3": 1,
        "2": 0,
        "5": 2,
        "10": 0,
        "6": 1
      },
      "histogram_type": 1,
      "bucket_count": 16,
      "sum_squares_lo": 176,
      "range": [
        1,
        15
      ],
      "sum": 28
    }
  },
  "TELEMETRY_TEST_KEYED_FLAG": {},
  "DEVTOOLS_WEBIDE_CONNECTED_RUNTIME_VERSION": {},
  "TELEMETRY_TEST_KEYED_RELEASE_OPTIN": {}
}

{
  "HISTOGRAM_1_NAME": {
    "KEY_A": { ... same type of histogram as in payload.histograms ... },
    "KEY_B": { ... same type of histogram as in payload.histograms ... }
  },
  "HISTOGRAM_2_NAME": {
    ...
  },
  "HISTOGRAM_N_NAME": {
    ...
  }
}