While upgrading mod_equella https://github.com/openequella/moodle-mod_openEQUELLA to the latest version we have noticed failing core unit tests. See https://github.com/openequella/moodle-mod_openEQUELLA/issues/110

However, during investigation we realised that actually core API incorrectly saves repository configuration to config_plugin table here https://github.com/moodle/moodle/blob/main/repository/lib.php#L311 It uses $this->_typename without prefixing it to plugin type so for equella it looks like set_config($name, $value, 'equella'); 

mod_equella code has changed as part of https://github.com/openequella/moodle-mod_openEQUELLA/commit/7225e988e5c4d1fa17a615069adcedcf85dc9509 and now they store config properly. This exposed core issues with repository configs.

Steps to replicate:

1. Bring mod_equella code from https://github.com/openequella/moodle-mod_openEQUELLA
2. Initialise unit tests env 
3. Run following core unit tests vendor/bin/phpunit repository/tests/generator_test.php
4. Confirm it fails