This plugin allows you to create certificates that can be automatically linked to a linkedin account. A button appears on the certificate page and automatically redirects to a form to add a certificate on linkedin.
Afterwards, visitors to the linkedin account can click on the certificate to obtain confirmation that the user has obtained the certificate.
Thanks to Mark Nelson markn@moodle.com for his plugin mod_customcert https://moodle.org/plugins/mod_customcert