If `.chezmoidata.$FORMAT` contains the following:

<!-- example-formats -->
```toml title="~/.local/share/chezmoi/.chezmoidata.toml"
fontSize = 12
```
<!-- /example-formats -->

Then the `.fontSize` variable is available in templates, e.g.

```
FONT_SIZE={{ .fontSize }}
```

Will result in:

```
FONT_SIZE=12
```

There may be multiple `.chezmoidata.$FORMAT` files in the source state. They
all *merge* to the root of the data dictionary and they are read in lexical
(alphabetic) filesystem order.

As an example, if I have four `.chezmoidata.$FORMAT` files in my
`dot_config` source directory, they will be merged according to the sort
order of the files:

```json title="dot_config/.chezmoidata.json"
{ "z": { "z": 3 } }
```

```jsonc title="dot_config/.chezmoidata.jsonc"
{ "z": { "z": 4 } }
```

```toml title="dot_config/.chezmoidata.toml"
z.x = 1
```

```yaml title="dot_config/.chezmoidata.yaml"
z:
  y: 2
```

The output of `chezmoi data` will include the following merged `z`
dictionary. Note that the value in `.chezmoidata.jsonc` overwrote the value
in `.chezmoidata.json` because of the lexical file sorting.

```json
{
  "z": {
    "x": 1,
    "y": 2,
    "z": 4
  }
}
```

Only dictionaries are merged; all other values (in particular lists) are
replaced.

`.chezmoidata.$FORMAT` files cannot be templates because they must be
present prior to the start of the template engine. Dynamic machine data
should be set in the `data` section of [`.chezmoi.$FORMAT.tmpl`][config].
Dynamic environment data should be read from templates using the
[`output`][output], [`fromJson`][fromjson], [`fromYaml`][fromyaml], or
similar functions.