I had to do a bit of searching on this! It's apparently called a Provisional Travel Document for Australian purposes. There are other names given to the same sort of thing by other countries.
It does say it is for emergency travel and it seems to be that this is available in countries where there is no other means to be able to obtain a valid Australian travel document.
Taken from
Australian Passports Determination 2015:
Subsection 9(1) provides that provisional travel documents may be issued to Australian citizens overseas when they are unable to obtain another Australian travel document; for example, because there is no Australian mission in the country they are in. These documents may be issued if an identity document is required to permit an Australian to travel from one foreign country to another country where there is an Australian mission where the person may obtain a passport or other Australian travel document. Provisional travel documents are issued by Australian Honorary Consuls and other countries’ missions (such as missions representing Canada) in places where Australia has in place consular sharing arrangements.
This would appear to rule out the OP's case where there was an Australian High Commission available.