I would like to add a custom setting on the Site Administration->Appearance->Navigation page.
But for the life of me, I cannot find any documentation that specially details the process of doing so.
I have tried to look inside the admin/settings/appearance.php file for some inspiration. But if I copy one of the settings and try to duplicate it for myself, I get a bunch of errors: like the whole "Appearance" admin settings tree is duplicated on the left block....
Would any of the kind developers here know documentation or tips on how to add a new "admin_settings_configselect" properly?
Thanks in advance!