The DPRR keeps a database of known alternate timestreams, classified by number. The home timestream -- "this Puzzlebox," so to speak -- is called Puzzlebox One; other timestreams are graded by degree of difference, ranging from Puzzlebox 1.001 through 987,445.452. The classification of any given timestream is a matter of laborious debate. So too is the discussion of what aspects of alternate societies are worth retrieving. (Implementation is left to higher authorities.)
DPRR members are selected from the most daring and stable-minded DTS members; this corps is colloquially referred to as the Chrononauts. They effect their extrachronological trips through a routine of drugs combined with a complex array of machines that send them to the target timestream with 96.7759694% accuracy. They wear heavy link chains hung with timepieces that allow those same machines to locate them anywhen and drag them back to Puzzlebox One. Retrieval success rates are at 100%, a matter of great pride for the DPRR.
Rates for unaltered retrieval hover at about 76.4547%, however. You'll come back, all right -- but your memories, your history, your own timestream, may well have been altered. As might others' memories of you.
Utterly losing one's personal history and identity the great risk for Chrononauts, and the primary reason for retirement.
Retrieved data and artifacts are carefully indexed and stored in the Specialized Collection for Parachronotic Artifacts, a collection maintained by a retired Chrononaut, The Archivist.