In general you do not have to declare any foreign income/assets that you do not remit to Malta as an ordinary Malta non-dom resident + tax resident.
For 2018 that will change a bit that there is the 5000 eur minimum tax for "ordinary" non-doms. This does not apply if you use any of their 15-25k a year residency schemes which will get you out of the 183 days rule but only make sense for small amount of people as residing only a few days will create problems with other countries etc pp.
That minimum tax is on the basis that you earn more than 35.000 eur in foreign income outside of Malta. If you just pay the 5k all is good.
If you don't pay it and claim that you generated less than 35k foreign income then they might / will inspect you and you will have to proof your foreign income is less.
In general the tax law probably has provisions for them to inspect you and ask for your foreign income etc but they have that anyways with the new reporting standards around the world.
In your tax declaration however only your Maltese sourced (physically being on the island no matter who you work for e.g. remote outside of Malta), any foreign income remitted to Malta as in transferred to Maltese bank account, payed with credit card, ATM withdrawal and in theory cash brought into the country so basically any form of electronic or cash currency being spent or brought into the Maltese jurisdiction e.g. a bank account is declared and taxed (except for some passive things etc).
So the usual "ordinary" non-dom will be paying 5k which will include remitted money (rent etc unless you moved to Malta with substantial previous assets which are remitted tax free), keep all the money in foreign accounts (as said previously using Maltese banks is batshit crazy anyways except for BOV but still 0 reason usually for this) and call it a day no matter what kind of foreign income is being generated.
For 2018 that will change a bit that there is the 5000 eur minimum tax for "ordinary" non-doms. This does not apply if you use any of their 15-25k a year residency schemes which will get you out of the 183 days rule but only make sense for small amount of people as residing only a few days will create problems with other countries etc pp.
That minimum tax is on the basis that you earn more than 35.000 eur in foreign income outside of Malta. If you just pay the 5k all is good.
If you don't pay it and claim that you generated less than 35k foreign income then they might / will inspect you and you will have to proof your foreign income is less.
In general the tax law probably has provisions for them to inspect you and ask for your foreign income etc but they have that anyways with the new reporting standards around the world.
In your tax declaration however only your Maltese sourced (physically being on the island no matter who you work for e.g. remote outside of Malta), any foreign income remitted to Malta as in transferred to Maltese bank account, payed with credit card, ATM withdrawal and in theory cash brought into the country so basically any form of electronic or cash currency being spent or brought into the Maltese jurisdiction e.g. a bank account is declared and taxed (except for some passive things etc).
So the usual "ordinary" non-dom will be paying 5k which will include remitted money (rent etc unless you moved to Malta with substantial previous assets which are remitted tax free), keep all the money in foreign accounts (as said previously using Maltese banks is batshit crazy anyways except for BOV but still 0 reason usually for this) and call it a day no matter what kind of foreign income is being generated.