If you UK guys haven't diverted to far from EU regulations you will get a "KTM-similar" setup for the rear. An extra add on for the plate which also holds stalk blinkers (must be 18cm apart) and plate light. Rear and brake light will be in the slim one up top.
And just like on any KTM/Husky everyone will remove the lower part and reconnect the nice slim one up top
There is an exemption for "off road" motorbikes in UK.
‘Off road’ motorcycles are constructed or adapted primarily for use off road. For example, their tires, suspension or ground clearance have been adapted for off road use.
You then do not need indicators, but it gets a little complicated if they are fitted, you may need to tape them over to pass the MOT inspection (not needed for the first 3 years from new).
To avoid issues you normally need to go to a tester who is aware of this and can help you with the test compliance.
As the EX comes with a Certificate of Conformity (COC), they would have needed to comply or have solutions in place for all eventualities. I have yet to see the "official" tail tidy, but this could their solution to enable the EX to have a full MOT.
My KTM EXC-F 350 does not have indicators and happily passes our MOT Inspection.