Composer registry: source is supported?

Gitea Usages
1

Is source (not only dist) in composer repository supported?
On ‘composer show’ i get empty source, even though composer.json specifies preferred source for selected package.

composer.json

    "config": {
        "optimize-autoloader": true,
        "sort-packages": true,
        "preferred-install": {
            "ecommercebox/*": "source"
        }
    },

❯ composer show ecommercebox/sw-plugin-xxx
name     : ecommercebox/sw-plugin-xxx
descrip. : xxx Shops API
keywords : 
versions : * 2.1.5
released : 2024-12-31, today
type     : shopware-platform-plugin
license  : proprietary
homepage : 
source   : []  
dist     : [zip] https://xxx.xxx/api/packages/shopware/composer/files/ecommercebox%2Fsw-plugin-xxx/2.1.5/ecommercebox-sw-plugin-xxx.2.1.5.zip 
path     : /Users/lutek/www/xxx.local/vendor/ecommercebox/sw-plugin-xxx
names    : ecommercebox/sw-plugin-xxx