Why is composer downloading all versions of dependencies?

Question

Yii

I'm trying to deploy a project on yii2 basic
, I'm doing it according to the standard

composer install

Not only does the composer itself work hard, but it also downloads all versions of dependencies.

a piece

composer.json

"minimum-stability": "stable",
"require": {
"php": ">=5.4.0",
"yiisoft/yii2": ">=2.0.5",
"yiisoft/yii2-bootstrap": "*",
"yiisoft/yii2-swiftmailer": "*",
"paragonie/random_compat": "1.4",
"dmstr/yii2-adminlte-asset": "2.*",
"twisted1919/yii2-shortcut-functions": ">=1.0",
"yiisoft/yii2-jui": "~2.0.0",
"twisted1919/yii2-options": ">=1.0",
"twisted1919/yii2-notify": ">=1.0",
"twisted1919/yii2-helpers": ">=1.0",
"nostalgiaz/bootstrap-switch": "^3.3",
"yiisoft/yii2-httpclient": "^2.0",
"kartik-v/bootstrap-fileinput": "dev-master",
"bower-asset/owl.carousel": "^2.2",
"select2/select2": "^4.0",
"yiisoft/yii2-authclient": "^2.1",
"bower-asset/malihu-custom-scrollbar-plugin": "^3.1",
"bower-asset/Sortable": "^0.8.0",
"omnipay/paypal": "^2.6",
"omnipay/stripe": "^2.4",
"2amigos/yii2-ckeditor-widget": "^2.0",
"bower-asset/jquery.payment": "^3.0",
"collizo4sky/omnipay-2checkout": "^1.5",
"omnipay/braintree": "[email protected]",
"kartik-v/yii2-widget-fileinput": "@dev",
"vova07/yii2-console-runner-extension": "*",
"yiisoft/yii2-imagine": "^2.1",
"twig/twig": "<2.0",
"bower-asset/speakingurl": "^13.0",
"kartik-v/yii2-widget-select2": "@dev",
"bower-asset/lazysizes": "^3.0",
"2amigos/yii2-highcharts-widget": "~1.0",
"kartik-v/yii2-mpdf": "^1.0",
"2amigos/yii2-multi-select-widget": "*",
"dvizh/yii2-gallery": "@dev"
},
"require-dev": {
"yiisoft/yii2-debug": "*",
"yiisoft/yii2-gii": "*",
"yiisoft/yii2-faker": "*"
},
"config": {
"process-timeout": 1800,
"fxp-asset": {
"enabled": false
}
},
"extra": {
"yii\\composer\\Installer::postCreateProject": {
"setPermission": [
{
"runtime": "0777",
"web/assets": "0777",
"yii": "0755"
}
],
"generateCookieValidationKey": [
"config/web.php"
]
}
},
"repositories": [
{
"type": "composer",
"url": "https://asset-packagist.org"
}
]

the screenshot shows how much time it has already taken to download 120mb, given that the Internet speed is 25 Mbps

Answer 1

Here - in the framework there are different versions in dependencies, apparently so that the developer can use the one he needs:
https://github.com/yiisoft/yii2/blob/master/compos...