Upon initialization of Packer, all the installed plugins will be automatically discovered.

Packer plugins must be located under the `plugins` sub-directory under Packer's main config directory
[PACKER_CONFIG_DIR](/packer/docs/configure#packer-s-config-directory).
If `PACKER_CONFIG_DIR` is either unset or empty, a default value of `$HOME/.config/packer/plugins` on UNIX,
or `%APPDATA%\packer.d\plugins` for Windows, will be used.

If the `PACKER_PLUGIN_PATH` environment variable is set, it will be used instead of `PACKER_CONFIG_DIR/plugins`.

-> **Note:** Prior to Packer 1.11 the `PACKER_PLUGIN_PATH` environment variable supported values containing
   multiple directories. Starting with Packer 1.11 and later this variable only supports a single directory.
