The Linda is a semiauto 9mm pistol that just exudes 1980s aesthetics. It was made along with a carbine version called the Terry, by Wilkinson Arms of California (later Idaho).
Both were named after daughters of the company founder, Ray Wilkinson. He would also later produce a Sherry pistol named after a third daughter and a Diane pistol, named after his second wife. The Linda uses a telescoping bolt similar in concept to the Uzi or its Czech predecessors, and it a surprisingly accurate gun, thanks to its fixed barrel and sights.
https://www.thefirearmblog.com/blog/2016/10/31/wilkinson-arms-linda/
Ian’s video: [14:30] https://youtu.be/ysrFXr2ozOk?si=
Yes, few more well-known designs like the ak74u have them too. The technical term would be a muzzle booster. The idea is to increase back pressure for more reliable function typically.
You’re right on the AKS-74u booster, but I don’t think that’s the case with the Linda. Looks more like a classic conical flash hider, so the user cannot see the muzzle flash while shooting.