Rondinax was and is sometimes misspelt (even by Agfa) as Rodinax. I have just found the following article by Olaf Nattenberg in Vidom, the publication of the German society, Leica Historica, entitled, Rodinax eine Leitz Tageslichtentwicklungsdose?!
This confirms that Leitz marketed the Rondinax 35 and 35U tanks from 1949 until 1954, an arrangement that continued in the USA until 1961. Examples from catalogues are quoted and some photographs of the 35U version shown; the lids of the these tanks were labelled as Agfa-Leitz Rondinax (USA) or Leitz Rondinax (Germany). It is also clear that no distinction was made by Leitz between the 35 and the 35U, both being called the 35 by Leitz (no photographs of the Leitz earlier version, i.e. not the U, are shown in the paper but my Pinterest site shows Leitz-badged tanks of both types). I still find that odd since the 35U was specifically designed to enable the special Leica labyrinthine cassettes to be used. Was the end of the marketing arrangement in 1954 connected with the launch of the Leica M3 that year?
Was it also a coincidence that the Essex 35 I and II (Rondinax 35 and 35U clones) were also marketed (and manufactured in UK) in Britain by Johnsons and NEBRO jointly at the same time in the early 1950s as Leica and Agfa were both marketing the Agfa Rondinax 35/35U?