a) $this->long_desc = $this->T_(''); returns the 'Header' of the current translation file. I know I shouldn't empty the variable like this, but returning the Header isn't correct either

b) Aborting an install where a DB is involved results in installing the plugin without the DB being installed.
There is an x to abort install at the point where it asks if it's correct to update the database if function GetDbLayout() is involved.
Better to abort installation of the plugin