"civ_sym_germania" is just the "civ_line_germania.png" file with the extension removed, no encryption was done. Then it's referenced in the icons file. "goggles_civ_germania" would be the id of your mod.
Code:
<Database>
<IconDefinitions>
<!-- Civ Symbol-->
<Row>
<ID>CIVILIZATION_GERMANIA</ID>
<Path>fs://game/goggles_civ_germania/icons/civ_sym_germania</Path>
<Context>DEFAULT</Context>
</Row>