WordPress at a glance
function is not described

install_plugins_upload() WP 2.8.0

Upload from zip

No Hooks.

Return

Nothing (null).

Usage

install_plugins_upload();

Code of install plugins upload: wp-admin/includes/plugin-install.php VER 5.0.3

<?php
function install_plugins_upload() {
?>
<div class="upload-plugin">
	<p class="install-help"><?php _e('If you have a plugin in a .zip format, you may install it by uploading it here.'); ?></p>
	<form method="post" enctype="multipart/form-data" class="wp-upload-form" action="<?php echo self_admin_url('update.php?action=upload-plugin'); ?>">
		<?php wp_nonce_field( 'plugin-upload' ); ?>
		<label class="screen-reader-text" for="pluginzip"><?php _e( 'Plugin zip file' ); ?></label>
		<input type="file" id="pluginzip" name="pluginzip" />
		<?php submit_button( __( 'Install Now' ), '', 'install-plugin-submit', false ); ?>
	</form>
</div>
<?php
}