Catalogs
Catalogs are containers for objects created in data editor. Each object created by the data editor belongs to one of the catalogs, which are distinguished by their function. These objects, or catalog entries, have a type, a parent and fields.
Type
Each catalog has a set of types it's entries can have, and each entry must have one type (for example Weapons can be [[Weapon: Generic|Generic], Legacy or Strafe). Type defines how the entry is used, and what fields it has.
Parent
Each entry can have a parent entry. The entry then inherits it's parent's field values for all the fields it doesn't have specified itself. This helps to save space in map files, as most of the fields will remain unchanged in many cases (for example units have ~100 of fields, of which ~15 are changed. The remaining 85 don't need to be specified, they are inherited from the parent, which is generic unit)
Fields
Depending on type and catalog, each entry has several fields that can be set. Fields are displayed in different colors, depending on where was their values set (gray are inherited from core entries, blue are inherited from Liberty entries, light green are inherited from other entries of current map, dark green are defined by this entry). Most of the fields can be read and changed with triggers.