composer.json is not findable by packages.drupal.org

Problem/Motivation

The MultiLangNG module has geeks4change/composable-inheritance as library dependency in its composer.json, but d.o packagist does not announce it.

Steps to reproduce

- (In a drupal site)
- composer require drupal/multilangng
- Expected: Dependency installed
- Experienced: Dependency NOT installed, breaks installation

Cross-checked:
- The dependency is on packagist.
- The composer.json contains the dependency
- Cloning the source, a `composer install` DOES install the dependency

BUT d.o packagist does not expose the dependency:

$ composer show -a drupal/multilangng
Info from https://repo.packagist.org:
name     : drupal/multilangng
descrip. : 
keywords : 
versions : * 1.0.x-dev, * dev-1.0.x
type     : drupal-module
license  : GNU General Public License v2.0 or later (GPL-2.0-or-later) (OSI approved) https://spdx.org/licenses/GPL-2.0-or-later.html#licenseText
homepage : https://www.drupal.org/project/multilangng
source   : [git] https://git.drupalcode.org/project/multilangng.git 128e400b525c76456c3c36dea39736f967805a40
dist     : []  
names    : drupal/multilangng

support
source : https://git.drupalcode.org/project/multilangng

requires
drupal/core >=9.3

Proposed resolution

?