It doesn't matter exactly what it's called - the key things are:
- it must be defined as housing or rental or somesuch
- your employer must "exercise proper control" that you do actually spend it on housing for yourself and your immediate family only (meaning they need to keep a copy of the lease and rental receipts)
- your employer needs to report it all to the Revenue
If these conditions are met then the housing is given a taxable valuable of 10% of the remainder of your salary (including bonuses). This has the slightly odd effect that the tax payable is independent of how much you actually spend on housing.
Details in this PDF from IRD:
http://www.ird.gov.hk/eng/pdf/pam44e.pdf