If $ENV{CFG} points to a config file of the form

a=b
c=d
[download]

and you call getCfg('e') then it returns (in order of preference):

$ENV{e}
$ENV{CFG_e}
$ENV{CFG_a_b_e}
$ENV{CFG_a_b_c_d_e}
$ENV{CFG_c_d_e}
$ENV{CFG_c_d_a_b_e}
[download]

and if none of those are defined it looks for a unique environment variable whose name ends in 'e' (if there's more than one, then it's an error).

I can't imagine how you could end up with all these oddly named environment variables. Google doesn't help much. Maybe some kind of i18n/l10n settings?