These creatures are exceptionally intelligent, able to reverse-engineer just about any alien tech they can study. Their primary cultural driver is boredom, and they pick up cultural aspects and hats from other races as they see fit. Their homeworld is unknown and long gone. They live instead in flotillas of impeccably maintained starships salvaged from just about anyone and anywhere.
First contact was a decidedly awkward affair, with several ships crippled on both sides, prisoners taken and epithets exchanged. Peace was regained at the cost of the human admiral's hat.
While they do engage in unmitigated scavengery and piracy, it's almost never mean-spirited unless you tick them off first. Then it's like being savaged by highly intelligent and somewhat impolite squigs. While they know full well that eating one's enemy does not gain one his powers, they have nevertheless been known to do so anyway from time to time. Also, like some aliens of fiction they admire the human female form. Nobody knows why, as nobody is quite sure the're not hermaphroditic.
Furthermore: Atomic welds and ceramic-alloy rivets on your ships do NOT constitute your external components "being nailed down". They can also survive hard vacuum for about five minutes, but they're not telling anyone exactly how.
While humans refer to them as "The Froggies", their name in the threat database is "Garoum" based on what they seem to call themselves. In fact, the term in their own language is shorthand for "Who is this fool who does not recognize us?" Their ships are similarly named: "Your finger you fool", "What an idiot who does not know what a starship is" and their flagship "Let's take his hat". The other major powers have tacitly agreed to let the Humans find this out for themselves.
In terms of society, they're like the Box Trolls with better social skills and bravery. Either that, or they're like extremely calm Nac Mac Feegle, all with engineering degrees. In any case, run the whole shebang through the same look and feel processes that produced the iPad with a bit more chrome and flash.