There isn’t much information available about this rather mysterious rifle. It was designed by the prolific Hungarian designer Rudolf Frommer, better known for his pistols, and was presumably manufactured by the FÉG company for which Frommer worked. Based on photographs, it appears to have been tested to some extent by the Austro-Hungarian Army, though for some reason it was not adopted. The photographs were taken around 1910, before World War I, so the Army may have been of the opinion that there was no official need for the rifle.
The rifle was a long recoil operated rifle with a detachable box magazine similar in concept to the French Chauchat that would appear five years later. The superficial similarities in design are so reminiscent of the SIG KE7 that I am almost certain that Pal Kiraly was probably the designer of this rifle. I am still trying to find out more about it, but information seems to be very scarce and I do not know if this rifle still exists today.
Probably standard Mauser cartridge, 7.92x57mm.
Frommer’s automatic rifle undergoing testing.
Rudolf Frommer (center) with his prototype automatic rifle
https://www.reddit.com/r/ForgottenWeapons/s/eECLY6xBWy