Artur made some suggestions for file extensions to be used / recommended for our formats / representations: (with comments by Jochen)

ASCII files

• .ort Open Reflectometry Text
  (German: place)
• .orp Open Reflectometry Pragmatic
  JS: pragmatic is associated with the content rather than with the representation.
• .ord Open Reflectometry Data
  JS: binary file also contains data
• .ora Open Reflectometry ASCII
  (Latin: pray, Italian: hour)

binary files

• .orb Open Reflectometry Binary
  (sphere)
• .ors Open Reflectometry Strict
  JS: strict is associated with the content rather than with the representation.
• .orn Open Reflectometry NeXus
• .orh Open Reflectometry HDF

model description

• .orm Open Reflectometry Model
• .orl Open Reflectometry Layers
  JS: model contains more than layers
• .ors Open Reflectometry Structure
  see also binary files
• .ord Open Reflectometry Description
  see also ASCII files

Attention: Several extensions are suggested in various categories!