functions like "encrypt" or "unparse_url" are invalid.
all functions in your plugin must be prefixed with the frankenstyle plugin name "modgamoteca" or in the case of activity module plugins the "mod" part can be excluded. Alternatively they can be in namespaced classes.
https://github.com/gamoteca/gamoteca-moodle-lti-plugin/blob/master/lib.php#L179-L197
functions like "encrypt" or "unparse_url" are invalid. all functions in your plugin must be prefixed with the frankenstyle plugin name "modgamoteca" or in the case of activity module plugins the "mod" part can be excluded. Alternatively they can be in namespaced classes.
more info on this is here: https://moodledev.io/general/development/policies/codingstyle/frankenstyle
note this is a blocker for plugins db approval.