The URL /mod/lti/openid-configuration.php is publicly available and it reveals the exact Moodle version, see

https://github.com/moodle/moodle/blob/main/mod/lti/openid-configuration.php#L53

There is no need to show full $CFG->release there. All the tool needs is the major version of the platform, e.g. 4.5 / 405.

MH EDIT: We've also discovered the same information is used/revealed by OpenAPI https://moodle.org/r.php/api/rest/v2/openapi.json - if possible we should also update this to major version only, consistent with the update to OpenID mentioned above.