AMD has delighted us with a fair share of fishy codenames over the last few months. The chipmaker's wild imagination has produced aliases, such as Sienna Cichlid, Navy Flounder, and Dimgrey Cavefish for its impending RDNA 2 graphics cards. The recent appearance of Green Sardine implies that AMD will likely continue this trend for unreleased processors that the chipmaker wants to hide from prying eyes.
The description from one of the patches reads: "Will be used for Green_Sardine, which is a new APU." AMD listed Green Sardine under Renoir, suggesting that Green Sardine is somewhat a variation or refresh for Renoir. If that is the case, Green Sardine could just be another codename for Lucienne.
Admittedly, there isn't any verified information on Lucienne. The low-powered APUs have been rumored to be a variation or refresh of AMD's current Ryzen 4000-series (codename Renoir) chips. Assuming that there's a link between the two, Lucienne might just end up with the same recipe as Renoir, which is Zen 2 cores combined with Vega graphics.
The Ryzen 7 5700U, which popped up a little over a week ago, is thought to be one of the first Lucienne APUs. There was little information on the APU to really form a conclusion. The Ryzen 7 5700U is reportedly an octa-core chip with simultaneous multi-threading (SMT), so it conforms to the maximum eight-core, 16-thread configuration on Renoir. If anything, the Ryzen 7 5700U should be the replacement for the Ryzen 7 4800U.
AMD will reveal new Zen 3 processors on October 8 and, consequently, the Radeon RX 6000 series on October 28. The chipmaker hasn't said anything about its APUs, though. Given that AMD has started deploying Green Sardine support, we suspect it won't be long before the fishy APUs launch.