To fix it, the .eg / .xn--4gbrim TLD registrar needs to contact the Mozilla Foundation in order to inform the Foundation of their official IDN name allocation policy, so that the native-script URL display can then be switched on for their domain.
Wow, talk about layer violation.
Yeah, security can be like that. Things which technically are treated the same are often semantically very different.
Is there a central place where various TLDs' IDN policies will be maintained ?
Yes, of course. See http://www.iana.org/domains/idn-tables/ It doesn't have the new IDN TLDs yet, but that's not surprising since ICANN didn't bother to tell the registries in advance that would be making the TLDs active. See http://www.circleid.com/posts/by_the_way_your_idn_is_live/ R's, John