ICAO Abbreviation and Codes are in ICAO Doc 8400
LOC means Localiser
These are Localiser check/step heights
Rat5 the Locator beacons (NDB) are indicated as LO (Outer marker) and LM (Middle Marker) on ICAO Charts. Most of these have been removed and now just have the check heights with a DME reference. I see this chart still uses LOM and then MM and IM which are non-ICAO standards