Thank you all for the explanations.
So it boils down to "IBM made it up" :)? when it mapped these notions of "department", "project", "tool" ("type") to the 44 characters of DSNAMEs.? Is that right?
One uses the "OTHER DATA SET" section when s/he wants to access DSs that have been named using a different scheme.
Apart from that, is there some more documentation about RFE? E.g., in the "OTHER DATA SET" what is the "'DATA' OPERAND"?
All the best
Marco